Free Shipping on all Spa Covers and orders over $100 Black Friday Deals!
Sunday - Saturday
7am - 7pm CST

Archive for the ‘spa chemicals’ Category

Foam in Hot Tubs

April 6th, 2015 by

image purch'd from istockFoaming in hot tubs and spas is a problem that every spa owner will have at one time or another. Even if you take great care of your spa, always ensuring good sanitation and filtration, foamy spa water can become an issue, so don’t be embarrassed if it happens to you! A little bit of foam is normal, especially if you run a bubble blower, but if there’s more than a thin layer…

You could drain the hot tub, and refill with fresh water, but that won’t always fix the problem. Read on for some fresh thoughts about foamy hot tubs and spas – and how to fix the foam!


What Causes Hot Tub Foaming?

  • Jokesters adding soap to the hot tub
  • Soft water, Calcium Hardness too low
  • High pH and Total Alkalinity levels
  • Soaps on skin and swim wear
  • Cosmetics and hair care products
  • Certain low grade spa chemicals
  • Body oil or oils from foods


How to Control a Foamy Hot Tub

The fast way to fix a foamy spa is to use anti-foam agents. Just spray a small amount over the surface of the water. The silicone based chemical immediately spreads over the entire surface, and destabilizes soaps and foams, popping all of the tiny bubbles!

A better way to control hot tub foam is to not have it in the first place. Using defoamers or anti-foam is just a temporary fix. It doesn’t do anything to solve the problem of how the soaps and oils got into the hot tub in the first place.


How to Prevent Hot Tub Foam

  • Balance the Water – pH, Alkalinity, Calcium.
  • Maintain a constant sanitizer residual.
  • Shower thoroughly before using spa.
  • Keep your head above water at all
  • Observe spa capacity limits, and limit soak time.
  • Rinse bathing suits washed with soap before use.
  • Replace your spa filter regularly.
  • Replace your spa water regularly.
  • Add sanitizer support, like minerals or ozone.


Spa Water Balance and Foamy Water

What’s water balance got to do with it? Nearly everything it seems; when pH and Alkalinity are high, and Hardness levels are low, the water becomes “slippery” and fats, oils and dirt combine into soaps. Soap also enters the spa on swimwear, skin or hair and finds it easy to multiply in a high pH, soft water environment.

Good water balance also allows your sanitizers to work more effectively, reducing contaminants and breaking up oils and scum that can become components of foamy water. Soap scum, or a bathtub ring around the spa is another result of poor water balance.


Using Anti-Foam in a Spa or Hot Tub

  • Balance chemistry first, for best results.
  • Clean or replace spa cartridge filter.
  • Follow dosage directions carefully.
  • Re-dose with Anti-Foam only after 8 hours.
  • Lock it up, to prevent re-dosing by others.


Cloudy Water and Hot Tub Foam

The often go hand in hand, cloudy water and foamy water, and you’ll rarely have one without the other. In fact, may of the conditions and symptoms are the same, and one can cause the other as well. The same tips listed to prevent hot tub foam apply to cloudy hot tub water.

Adding air into the jets, passive air or pumped air (blower) will exacerbate a foaming problem, as it will entrain air (tiny bubbles) into the water, giving an appearance of cloudy water, but also whipping up the water into a foamy froth.


Chemicals that Cause Foam in Hot Tub

  • dont-use-household-cleaning-productsLow grade bromine or chlorine products
  • Low grade algaecides (10%)
  • Biguanide sanitizer chemical
  • Household cleaners or soaps


Biofilm and Hot Tub Foaming

biofilms-in-spa-plumbingWe’ve reported on Biofilm in Hot Tubs many times on this blog. In cases where hidden biofilm is allowed to build-up, they can provide and endless source of oily scum that can easily turn into a foaming problem. If you’ve tried everything else to reduce spa foam, but it keeps returning, consider using a product to strip the pipes and equipment of any biofilm. Spa Purge or Jet Clean are two good products. Use annually to prevent new colony formation.


How much Foam is too much Foam?

Just about every spa will have some small amount of foam, and even on well maintained spas, you may notice foam beginning to develop as your spa water gets older. Yes, foamy hot tub water can be a sign that it is time to change the spa water.

When there is more than an inch of foam however, it begins to get annoying, but the larger reason to deal with spa foam is that foamy water becomes an ideal transport medium for bacteria, emulsifying it to the surface where it can be more readily absorbed by bathers.



too-much-spa-foamIf you were a victim of a joke, or have a teenager who thought Foam Party in a Hot Tub would be a good idea – drain the hot tub, flush the lines out several times and clean all surfaces before it’s refilled. After refilling, balance and shock the water. If you still have soap residue, use Jet Clean or a similar Purge chemical to clean the pipes.

Foam hot tub parties may be fun, but you really need to clean well afterwards, and there may still be soap residue after draining the spa several times. Plus, it can be unsafe – so do yourself a favor and just say no to hot tub foam parties!


- Jack



Hot Tub Chemical Storage Ideas

March 23rd, 2015 by

Is the Container Store a favorite hang-out for you? Do you spend hours organizing everyone’s sock drawer in the house? Do you feel a calm sense of control when your surroundings are neat and orderly? Me too – storage and organization is kind of a hobby of mine. My Pinterest page is filled with ideas for organizing around the home and office.

Today I bring you some ideas for organizing spa chemicals, so they are visible and orderly – but also, and more importantly safely out of the reach of children and pets. Spa chemicals also need to be kept cool and dry, and be separated for safety. More on that later, but first, I have 4 ideas for organizing your spa chemicals and cleaners.


spa-chemical-storage-in-a-bench1. Deck Bench Hidden Storage

Part deck railing, part bench, the flip-up lid on this custom made wooden bench flips up to a large expanse for chemicals, filters, cleaners, and cleaning tools.

The problem with this design however is that the storage is outdoors, and subject to wide temperature extremes and humidity. High heat can cause some spa chemicals to expand and very cold temperatures can reduce potency. Moisture from rain or humidity is bad on many levels for spa chemicals. And, unless you add a latch to the lid, this design won’t keep out children.



spa-chemical-storage-rubbermaid2. Rubbermaid Storage Cabinet

This type of cabinet is perfect for garage or shed storage, and is suitable for wall mounting, to keep it off the ground, away from water and children. It also has a latch which can be locked.

You can install this indoors as well, to store your chemicals in a climate controlled environment. A plastic cabinet like this one will not corrode like metal cabinets will, in the presence of chlorine or bromine gas.



3. Over the Door Organizer

You’ve seen these used for cleaning products or shoes before I’m sure. I have used one for my shoes for years, but they can also be useful in office supply closets, laundry rooms and in spa storage closets.

Of course, this idea may not store all of your spa chemicals or cleaning tools, but it can hold the regular size bottles and test strips, and cleaners.

This has some great advantages in that the products are kept separate and snug in their own pouch, away from each other.



sterilite-bin-for-spa-chemicals4. Sterilite Storage Bin

A favorite method of thousands of spa owners, keeping your chemicals in a portable box allows you to keep them high and dry, even if you store the spa chemicals outside.

Being portable, this type of storage option let’s you move the chemicals indoors, and store in a locked closet or on a low shelf.

The problem with this method is that bottles tend to get thrown into the box, which could cause an accidental chemical spill. If you use this method, use several smaller boxes to separate sanitizers from balancers.


Spa Chemical Safe Storage Tips

  • Keep spa chemicals cool, 50-75 degrees F
  • Keep spa chemicals dry, safe from flooding and humidity
  • Store sanitizers separately from each other, and away from other chemicals
  • Twist lock the lid tightly on all chemicals after use
  • Rinse measurement containers before and after use
  • Keep chemicals safely out of reach of children
  • Never store chemicals loose on a shelf
  • Never use a shelf that may collapse in an earthquake


So get organized! If your spa stuff isn’t so safely or conveniently stored, use these storage ideas for your hot tub chemicals – and get yourself organized and ready for spa season!


Carolyn Mosby
Hot Tub Works


Children in Hot Tubs

March 12th, 2015 by


Children in hot tubs – is it dangerous?

When my children were young, many years ago, I can remember telling my husband; “they’re not just little adults, you know…”.

Especially for children under 5 years old, with bodies still growing, a hot tub could be unhealthy or possibly dangerous.

The first problem with children using hot tubs involves their ability to regulate temperature and the possibility for hyperthermia, or overheating very quickly, in a spa that is heated to over 100°.

The second issue with kids in a hot tub are concerns of bacterial infection, by absorbing pathogens through the skin, ears, eye, mouth and airways.

And third, the most important reason – is that unsupervised access by children under 5 has resulted in hundreds of drowning incidents by children under 5 years old.

Let’s take a look to see what health experts have to say about children in hot tubs.

  • CDC says: “Exclude children less than 5 years of age from using hot tubs.”
  • Red Cross says: “Children under 5 should not use a hot tub.”
  • APSP says: “No young child should be allowed in a hot tub until they can stand on the bottom and have their head remain completely out of the water.”
  • AAP says: Use a rigid, lockable cover on a hot tub, spa, or whirlpool, or fence in all 4 sides as you would for a swimming pool”
  • Mayo Clinic says: “Young children can quickly become overheated in a hot tub or spa.”
  • CPSC says: “Hot tubs pose a drowning risk to children and an overheating risk for young children.”
  • MHP says: “Hot tubs are too hot for young children, may have high bacteria, and the drain in the tub can trap children.”

The Problems with Children in Hot Tubs

HIGH TEMPERATURES: Young children have skinny little bodies with thin skin. They absorb heat much more rapidly than adults, and can become overheated in just minutes in a spa at 104°, which can lead to dizziness, nausea or even unconsciousness. Children under the age of five heat up four times faster than adults, and also struggle to breathe the very hot and humid (steamy) air coming off of the water. Children older than five should limit exposure to hot water, both by reducing spa temperatures to 100° or less, and limiting soaking time to under 10 minutes.

EXPOSURE TO BACTERIA: In a public spa or hot tub, you never know if the water is sanitary, and if the spa is heavily used – its’ probably not. My advice is to never allow children to use a public spa, where they can be exposed to mycobacteria and pseudomonas or the parasite cryptosporidium. Skin infections, ear infections, or even respiratory infections are possible with adults and children, but children are more susceptible to attack. In a private hot tub or spa – assuming that your spa is not overused and is carefully maintained, and everyone showers fully before using the hot tub – the risk of bacteria exposure may be less. However, sickness can still occur if too many people are in the spa, or if the child stays in too long, or goes underwater, allowing exposure through nose, ear, eyes and mouth. Using the air blower in a spa can produce more aerosol bacteria, released as the bubbles reach the surface.

DROWNING / NEAR DROWNING: A spa or hot tub should always be secured by a locking spa cover, which will make it unlikely that a young child can gain access. Children older than five, working as a team, can manage to remove a spa cover – I can tell you from experience! A hot tub in the home or backyard can be every bit as dangerous as a swimming pool, and should be regarded as such. Drowning can occur from a bump on the head, overheating or from becoming entrapped or suctioned to the spa drain outlet. Teach your children to never use a spa or hot tub without constant adult supervision.

If you MUST allow your Children in a Hot Tub

The hard part is – kids LOVE hot tubs, and it’s a magnet for them. They are drawn to it because it’s close to their size, like a mini-pool, and for kids like mine, if you don’t let them do it while you are watching, they’re going to do it while you are not watching. If you really want to allow children older than 5 to use your private / home hot tub, here are some sensible rules to make it safer.

  1. Everyone Shower before using spa
  2. Turn down temperature below 100°children-in-hot-tub
  3. Limit soaking time to under 10 minutes
  4. Keep heads above water at all times
  5. No more than 3-4 kids at a time
  6. Constant adult spa-side supervision
  7. Have warm towels and cool drinks ready


Carolyn Mosby
Hot Tub Works


How To Clean a Hot Tub that has been Sitting

February 24th, 2015 by

how-to-clean-a-spa-that-has-been-sittingIt doesn’t take long for spa water to go south when the hot tub has been sitting for days or weeks without being filtered or sanitized. How long? In moderate temperatures, spa water can stay fresh for up to two weeks, if covered tightly.

Spa water that sits longer than a week or two will begin to grow algae and bacteria, even without light, under a dark spa cover. Spas that sit untended will begin to grow biofilm or bacterial colonies – the kind of scum you see in a toilet that hasn’t been used or cleaned in awhile (sorry for that analogy!).

For spas and hot tubs that have been sitting, unused and unmaintained, for a period of longer than a few weeks – here’s the process to bring it back online.


Before you do a lot of work cleaning the hot tub, make sure that the spa pump and filter are operational. Add water if needed to bring the level up to mid-skimmer, covering the spa filter, which may need to be replaced with a new filter cartridge.

Turn on power at the circuit breaker, then open up the spa cabinet to find the spa equipment. Reset any popped GFCI outlets, and power up the spa pack. Check that all valves are open, before and after the pump, and take a good look for any leaking water under the spa.

Using the spa side control, run the spa pump on low speed and high speed briefly, which will help dislodge gunk in the pipes. Some spas have two pumps, a circulation pump and a jet pump; test them both to be sure that they will be operational after you drain & clean the hot tub.


Draining the spa is the best way to clean a hot tub that has been sitting for awhile. If your water is in fair condition, hazy but without visible algae or biofilm growth, skip ahead to the next step and purge the plumbing, to clean a hot tub without draining.

draining-a-hot-tubTo drain a spa or hot tub, look for the drainage port or hose. Some spas have a small access port at the base of the cabinet to drain water. If not you will usually find a short hose or a hose connection at the lowest point of the spa. Pull out the hose, or connect a hose, and let the water drain by gravity. You can also use a submersible pump to drain a spa. Be sure that the power to the spa is OFF before draining.

As the spa is draining, if the water condition is really bad, use a garden hose to spray off the spa surfaces. You can also spray into the skimmer, or spray water directly into the spa jets, to help loosen slimy gunk. Just be careful not to spray the spa pack, or spa equipment (pump, filter, heater).


Now that you’ve removed the funky, gunky water from the hot tub (or if you want to clean a hot tub without draining), the next step is to purge the spa, which means to add a chemical that will remove the slimy biofilm that lines the inside of the pipes, and has made a home in various nooks and crannies in the spa air and water plumbing.biofilm-in-spas-and-hot-tub

You can use Natural Chemistry’s Spa Purge, or Leisure Time’s Jet Clean. Follow label directions, adding it to the spa with the pump system running. In a very short time, you will notice the funk and gunk rising to the surface, as a brown foam. Turn on the jet pump and blower to help dislodge any remaining bacterial colonies.


Drain the spa again, using a hose or rag to remove the scum around the top of the spa, cleaning as the water level drops. When completely empty, use sponges or a wet/dry vac to suck up the last bits of water.

One more time to the well! Refill your spa with fresh water. When full, test the water chemistry and add adjustment chemicals if needed to balance the pH, alkalinity and calcium hardness. Add a bromine booster (if you use bromine tabs), and then shock the hot tub with 1-3 tablespoons of spa shock, following label instructions.

A new spa filter may also be in order, to keep the hot tub water clean and clear. Replace your spa filters every 18 months, or every 12 cleanings, whichever comes first.


Happy Hot Tubbin’

Daniel Lara
Hot Tub Works





Spa & Hot Tub Maintenance

February 20th, 2015 by

image from ThermospasWell hello again, my dear readers; I would have thought this topic would go to one of our more technical writers, but my hot tub was voted as the most well-maintained, and they asked to know my secret! :-)

Flattery will get you everywhere I suppose,  so here I am with some basic spa and hot tub maintenance information. What do you need to know to take care of a spa or hot tub? Read on, dear reader.


Care = Prevention

When we talk about spa care and hot tub maintenance, you really are practicing problem prevention.  There are a number of things that are done on a regular basis, regular hot tub maintenance tasks, and then there are those best practices or methods that are used to keep your spa running well, while being energy friendly and safe for pets and children.


Spa & Hot Tub Chemical Maintenance

  • Test spa water for pH, chlorine/bromine, alkalinity and calcium levels 2-3x per week.
  • Adjust pH, alkalinity and calcium as needed. Maintain a constant chlorine/bromine level.
  • Clean the spa cartridge filter when the pressure gauge rises 7-8lbs, or 1-3x per month.
  • Set the 24 hr pump timer to run on low speed for a total of 12-18 hours daily.
  • Drain the spa every 3 months to prevent buildup of dissolved solids.
  • Refill the spa using a pre-filter that screws onto a garden hose.
  • Shower before using the spa, and Shock after using the spa.


Spa & Hot Tub Equipment Maintenance

  • Spa Covers: Use a spa cover lift, air-out the spa cover 2x per week, clean & condition spa cover 3x per year.
  • Spa Filters: After cleaning allow it to dry fully before reinstalling. Use filter cleaner 2x per year, replace filter every 1-2 years.
  • Spa Pumps: Run on high speed only during use or adding chemicals. Don’t allow pumps to run dry, or with an air-lock, or low water level.
  • Spa Heater: Maintain proper water chemistry and keep a clean cartridge filter to protect your heater element.
  • Spa Cabinet: Protect from direct sun, lawn sprinklers or rain splash around edges. Stain and or seal the surfaces as needed.
  • Spa Shell: Acrylic or plastic spas should be polished when emptied, wood hot tubs require cleaning without chemicals.


Saving Money & Energy

  • For daily use, keep the temp at 98°, or 94° if you only use it every 3-4 days.
  • Bump up the temperature to 101° – 104°, and then shower before using spa.
  • Keep your spa cover tightly fitted, and for extra insulation, use a floating foam blanket.
  • For colder areas, add R-30 insulation to poorly insulated spa cabinets.
  • Set the spa timer to operate mostly outside of peak daylight energy use hours.


Spa Safety

  • Covered: Don’t forget to always keep the spa tightly covered, with safety clips attached.
  • Locked: Indoor spas should be in locked rooms; lock doors and fences to outside spas.
  • Secure: Be sure that spa drain covers are safe and secure.
  • Spa Rules: Use safety signs and teach children the spa is only used with adult supervision.



Make a list or set a reminder in your calendar to not forget these important hot tub maintenance tasks. And if you have someone else in your family doing it as a chore, believe me, you better follow up behind them!

I hope I was able to answer all of your questions about taking care of a spa! Leave a comment if you have any other ?’s about hot tub maintenance, or you want more information on any of my tips above!


Carolyn Mosby
Hot Tub Works



Myths about Spa & Hot Tub Chemistry

July 21st, 2014 by

5 myths-about-hot-tub-chemistryWhen you advance beyond your basic pH and bromine levels to more advanced hot tub chemistry, you become aware of certain tenets or principle beliefs of managing a hot tub.

Many are useful, such as adding only one chemical at a time, or maintaining good alkalinity to control pH bounce when several users get in the spa.

But some of the things I’ve heard, are either incorrect, or need some further explanation. Let’s take a look at some of the common misconceptions in treating hot tub water.


MYTH #1: Pools and Spas are the Same – or – a Spa is Just a Small Pool

A spa is a small pool, true, but that’s where the similarities ends, especially when regards to water chemistry. Precisely because it is such a small pool of water, hot tub water chemistry drastically changes when several users jump in the tub. pH can rise quickly to over 8.0 and render your sanitizer much less effective.

The temperature also has an effect upon how solids behave in the water. Bicarbonates, minerals and metals all respond a little differently, activated by temperatures over 100 ° towards greater scaling potential.

MYTH #2: Shocking is Needed Every 5-7 Days

Perhaps, if you are using it regularly. Shocking, or oxidizing your spa water, is done by adding a granular oxidizer (not pool shock), to break apart oils, dirt and any living algae, bacteria, viruses or mold that could be in the water. Shock the spa after you use it, following label directions.

If you have not used the spa all week, it’s not necessary to shock the water. But, if you haven’t used it in several weeks, it would be good to shock several hours before you use the spa, and then again afterwards, always testing the pH and alkalinity first, and adjusting if necessary.

Remember to leave the spa cover open for awhile after shocking with chlorine, to allow it time to gas off.

MYTH #3: Ozone (or UV) & Minerals are the only Sanitizer Needed

Perhaps, if you rarely use the spa, and you always shower beforehand, and you replace your spa filter every 12 months. Ozone is a very powerful sanitizer, as is UV (Ultra Violet) light, but they have some trouble with reaching every H2O molecule, and they only work when the spa pump is operating. Minerals are effective at controlling algae and some bacteria, but fall short of full sanitation.

For a sanitary spa, disinfecting the water with a regular sanitizer like bromine tablets, and regular shocking with MPS or Non-Chlorine spa shock is indicated.

MYTH #4: You Don’t Need to Check Calcium Hardness in a Spa

Having soft water (below 150ppm) in a spa leads to a corrosive water environment and having hard water (above 250 ppm), leads to scaling conditions. The higher temperature factor used in the Langelier Saturation Index, makes an acceptable calcium hardness level much more restrictive in spas and hot tubs.

For balanced spa water, check the calcium hardness level of your fill water each time you fill. Add calcium increaser if below 150, and run a higher Alkalinity level of 100-120. If you have hard water above 250, adjust your other chemical levels for balanced water, to use a lower alkalinity, in the range of 70-90.

MYTH #5: My Spa Filter Still Looks New, so it Must be Good!

You could say the same about a Nature2 spa stick, looks good on the outside, but inside it’s minerals are depleted. Over time, spa filter cartridges lose their ability to trap particles and harmful bacteria that can end up forming biofilm in the deep recesses of your spa plumbing.

Even though it may look new, each time a spa cartridge is cleaned, the fibers invisibly separate a little more, and the cartridge passes through a little more dirt. After 12-15 cleanings – a spa filter may be only doing half the job that it did when new.

Replace your spa filter cartridges every 24 months, or every 12 cleanings, whichever comes first.



Gina Galvin
Hot Tub Works



Hot Tub Folliculitis – Preventing Pseudomonas

July 17th, 2014 by

FOLLICULITISnoun \fə-ˌli-kyə-ˈlī-təs\ – inflammation of one or more follicles especially of the hair.

It’s a skin infection that produces an itchy rash with red bumps.

Pseudomonas Aeruginosa is a germ usually responsible.


Pseudomona… What?

pseudomonas-4Hot Tub Rash is a faster way to say it, easier than either folliculitis or pseudomonas aeruginosa! Let’s call our germ “Pseudo“; Pseudo is one of the most common bacterias in our modern society. It is naturally occurring nearly everywhere, and poorly maintained hot tubs present a particularly nice home for the pathogen.

Pseudo is also responsible for over 10% of all hospital infections. In addition to dermatitis, pseudomonas also causes gastrointestinal, urinary and respiratory infections. It’s a very opportunistic bugger, exploiting hosts with a variety of entry points.

In a hot tub that is poorly filtered and sanitized, pseudomonas can thrive, and as you soak in the water, your pores open up, and the pseudo just swims right inside, and makes a home near the root of the tiny hair follicles.

The rash usually appears on legs, buttocks and back, but hot tub rash can appear nearly anywhere on the body. The rash can begin to appear within a few hours, but may take up to 24 hours to become noticeable. The rash frequently appears under the swimsuit areas, due to continued exposure even after leaving the water.

Preventing Pseudomonas

To make sure we get the information correct, I went straight to the experts. Prevent hot tub rash in your spa by following these tips from the CDC’s Pseudomonas Fact Sheet.

  • Remove biofilm slime regularly by scrubbing and cleaning.
  • Replace the spa filter according to manufacturer’s recommendations.
  • Replace the water in a hot tub regularly.  Here’s how.
  • Maintain pH levels in the 7.2-7.8 range.
  • Maintain sanitizer levels; 2-4ppm chlorine, or 4-6ppm bromine.

Public Spas & Hot Tubs

The fact is, most cases of hot tub rash occur in public spas – hotels, resorts, rec centers, gyms. It’s much less common in well maintained home spas. Public spas have high levels of guests, which pummels the sanitizer and pH levels, and quickly allows bacteria to form, unless the operator is constantly monitoring the chemistry and filtration.

To safely use a public spa, which I do on occasion while on vacation – here’s a few tips of my own:

  • I always pack some spa test strips to discreetly test the spa pH and sanitizer in a public spa.
  • Limit your soak to 20 minutes, afterwards, wash yourself and your swimsuit in the shower.
  • Change into dry clothes, don’t stay in your swimsuit.

Hot Tub Rash Treatment

In most cases, the rash will disappear on it’s own in otherwise healthy individuals. Itching can be reduced with a calamine lotion, or similar anti-itch ointment.

In individuals with compromised immune systems, or if symptoms persist past 3-4 days, or appear to be spreading, visit  your doctor or a dermatologist, who may prescribe an antibiotic medication or antifungal cream. Lab tests could be performed to determine the exact type of bacteria or fungus.


Happy Hot Tubbin’

Daniel Lara


Minerals, Ozone and MPS for a Chlorine Free Hot Tub

June 19th, 2014 by

ozone-minerals-mpsIf you are interested in a method to operate a spa or hot tub without chlorine or bromine, you’re in the right place.

I have been bromine free in my spa for about 7 years. It’s a 400 gallon Marquis spa, that gets used 2-3x per week, by kids and adults. It’s an easy method that I’ve kept hidden until now – a great way to keep a spa or hot tub halogen-free, while ensuring that the water stays sanitary and healthy.

But why? Why would I want to operate a tub without chlorine or bromine ~ some of you may ask. I’ve always found it irritating, to my skin, hair and nasal passages, and it can be hazardous to store, plus I feel like our planet could use a little less Bromine.

Minerals + Ozone + MPS for a Non Chlorine Hot Tub

The secret to going bromine-free isn’t hard to follow; I use a mineral cartridge, an ozonator, and I shock the spa with MPS, non-chlorine shock, after we use it, or at least weekly if no one has used it, which is rare.

Minerals: I usually use the Nature2 spa stick, as I call them- or you can use the Filter Frog, or the Leisure Time spa mineral stick.We also have the SunPurity mineral purifier for Sundance spas and the Hot Springs Silver Ion Purifier

Just drop them in your filter, and the rushing water pulls out copper and silver ions that do a bang-up job of busting apart contaminants in the water. After 4 months, they need to be replaced, which I time to be at or around the time that I am changing the spa water.

Ozone: A spa ozonator puts ozone in the water, which zaps anything that comes near it. Some of the nicer model spas have a built-in ozonator, but if not, you can easily add an ozone unit to the spa – like the MCD-50, which is only around $100.  After12-18 months, the manufacturer recommends the Renewal Kit, they may last longer however.

Ozone complements the killing preferences of minerals, removing the really hard to kill stuff, like bacteria and viruses. But even ozone, as powerful as it is, has limitations with an imperfect delivery system. So, I supplement ozone + minerals with MPS.

MPS: After we get out of the spa, I just sprinkle in a dose of monopersulfate, aka MPS, as we call it around here. I let the jets circulate for a few minutes, and then shut it down to low speed and close the cover. No waiting for it to ‘gas-off’, like with chlorine shocks.

I use the HTH Spa non-chlorine shock, it’s the strongest type of MPS we sell, and it has a good price. We have other brands and formulations of MPS, by Leisure Time and Rendezvous and we carry the full line of Zodiac Cense, MPS & Aromatherapy in one!

Other Tips for a Chlorine Free Hot Tub

  • Drain the tub every 3-4 months. Before draining, use Jet Clean to fight biofilm.
  • Change the spa filter regularly, every 12-24 months, to reduce your sanitizer demand.
  • Don’t be afraid to double the MPS dose if you’ve had a full spa, with many users.
  • Run the filter 20-24 hours per day, to keep the minerals and ozone circulating.
  • Keep your water balanced, especially your pH and alkalinity.


Carolyn Mosby
Hot Tub Works


Spa Chemical Start Up Guide

May 29th, 2014 by


Balancing your spa or hot tub water after draining and refilling is an important step for many whose tap water is less than perfect.

Doing it in the right order is even more important, to prevent problems and make adjustment and balance something that takes just a few hours, not days.

Many of our customers have fill water that is very hard (or very soft), very acidic (or basic), and loaded with metals or metals, phosphates and nitrates, or silt and sediment. Not good spa water.

My spa fill water is from a well, and even after water treatment, it has a high pH and is full of minerals and metals.

Here’s my 3 step process for refilling a spa, balancing the chemistry, and starting sanitation.


number_one_400_wht_9875 - image from PMAs I mentioned, I’m on a well, but even if I wasn’t I would use a pre-filter to fill my spa. City water often contains high levels of chloramines, ammonia and phosphates. If you have a DPD pool or spa test kit, test the water sometime, you may be surprised!

Our Pre-Filter removes all types of chlorides and sulfides, minerals, metals and contaminants. Filters down to below 1 micron in size, it even softens hard, scaling water and removes odors! Just connect it to a garden hose and fill your spa. It’s good for 3-4 fills before the filter clogs.

The only way this could be better would be if it also balanced the water (alkalinity, pH, calcium)!


number_two_400_wht_9869 - image from PMThe first step of course is to test the water with a reliable test kit or test strips. Test kits are more accurate, but most people I know test the spa water with test strips.

Alkalinity First! Mine is always a little low, around 50ppm, so I add Alkalinity Increaser first, to bump it up to around 100ppm. This helps to hold your pH level steady when several hot tubbers jump in the water, so don’t neglect your Total Alkalinity level.

Second is the pH adjustment. I add a pH decreaser (acid), to lower the pH to around 7.4, or between 7.3 and 7.5. With high pH like I have, scaling of calcium can result, and it also causes the sanitizer to work harder, and makes it easier for bacteria and other pathogenic stuff to grow. A low pH, below 7.2 is equally troublesome, and below 7.0, the water becomes acidic and can corrode finishes, damage wood, or harm sensitive spa components.

After my Alkalinity and pH adjustment – I let the spa circulate for about 10 minutes or so, and then I adjust the calcium hardness. In my case, our water is extremely soft, and is only about 100 ppm. I add Calcium Booster to the water to double it, to 200 ppm. A range of 200-400 ppm keeps spa water from becoming aggressive in it’s desire for calcium, which can lead to corrosion and staining. Again, I let the spa circulate for about 10 minutes before starting sanitation.


number_three_400_wht_9871 - image from PMThe first thing I do is boost the bromides in the water by shaking in some Brom Booster, about two tablespoons. This is an important first step if you use bromine tablets in your hot tub. If you don’t add sodium bromides, it can take days or weeks to build a bromine residual, which leaves your spa vulnerable to bacteria.

Immediately after the bromides are added, I shock the spa with chlorine granules. I normally use MPS (non-chlorine shock), but after a refill, I like to use a chlorine shock to kill anything in the fill water and to activate the bromides.

Keep the spa cover open for a few hours after shocking, to allow gas to escape. The spa is not ready for use yet, not until the sanitizer level has fallen below 5 ppm. Plus, it’s not hot yet anyway – so before bed, I replace the spa cover and turn up the heater. molecular_structure_expand_anim_150_wht_14299

The next day I check chemistry again, and make any additional adjustments. When perfect, I always smile and give myself a pat on the back!

Check and balance in the right order and you can make quick work of spa and hot tub start-ups!


- Jack


Chlorine or Non-Chlorine Shock for Hot Tubs?

May 19th, 2014 by


Spa and Hot Tub Shockwhat’s better – chlorinated granules or non-chlorine shock?

This post takes a look at the differences between two types of oxidizers used for spa shock treatments – Sodium DiChlor (chlorine granules) or MPS – Monopersulfate (chlorine free).

WHY SHOCK SPAS & HOT TUBS? Oxidizers are added to pools and spas to destroy pathogens like bacteria and viruses, and also organic contaminants that lead to algae growth.

The second main reason is to destroy molecular combinations between your main sanitizer (chlorine or bromine), and other organic matter, which create foul smelling -amines in the water.

WHEN TO SHOCK A SPA? The best time to shock a spa is after you have used the spa, or every 7-10 days. Don’t shock just before using the spa which will reduce it’s effectiveness, and could cause skin irritation. Wait at least an hour after shocking (with MPS), while circulating the water with the spa cover open, before getting in the tub.

HOW TO SHOCK A HOT TUB? Follow the label instructions, for specific dosages. Check your pH first, and adjust to within 7.2 – 7.6. This will allow the oxidizer to work harder, with a pH in the lower half of the scale. Just shake the required amount over the water, being careful of winds, which could blow the powder in your face. Don’t rinse off the cap or scoop in the water, keep it dry and clean at all times for safety. Keep the cover open to allow for gassing off, an important part of the process.

WHAT TYPE OF SPA SHOCK IS BEST? Finally, we are at the meat of this post – which is better for spas and hot tubs, MPS or chlorine shock? Let’s create some distinctions between the two types of spa shock, by looking at benefits of each, not shared by the other.


SPA-SHOCK-PRICES-COMPARISON-CHARTHow do Chlorine Granules compare to MPS in terms of price? Is there a large difference between the two? Our chart shows 4 chlorine shocks, 5 MPS shocks, and one blend, Replenish, which contains MPS, with some chlorine added.

Chlorine granules come out a bit cheaper by the pound than MPS spa shock, which has a much wider price range, all higher per pound than chlorine, with the notable exception of Activate shock.



SPA-SHOCK-STRENGTH-COMPARSION-CHART-2The reason that DiChlor shock is used in spas, is that DiChlor is more stable at higher temperatures and has a near neutral pH level. Spa shocks are particularly fine, more of a powder than a granular, so that they dissolve quickly.

All 4 of the chlorine hot tub shocks are 56% Available Chlorine. Among the 5 non-chlorine spa shocks, all are blends of MPS in different formulations, with different percentage of MPS.

If one was to generalize the relative strengths of MPS and DiChlor, it could be said that both Dichlor and MPS have equivalent ability as an algaecide, bactericide and virucide. Dichlor shock may have an edge for spas that are heavily used, or in need of high levels of oxidation.



Dichlor-molecule - RSC.orgCHLORINATED GRANULES:

Although there are many types of pool shocks available, using Calcium or Lithium or Sodium Hypochlorite, chlorine hot tub shocks are primarily made with Sodium DiChloro-S-Triazinetrione, or DiChlor for short.

  • Neutral pH, Quick dissolving
  • Sanitizes and oxidizes pathogens and organic contaminants
  • Lower price point

MPS-potassium-peroxymonopersulfate  from rsc.orgMPS SHOCK:

There are a few formulations of MPS, but most of the monopersulfate sold for spas and hot tubs is a blend of MPS, primarily purchased from DuPont, and packaged for resale under many brand names.

  • Low pH, Quick dissolving
  • An excellent oxidizer and a fair sanitizer
  • Does not contribute calcium or cyanuric acid to your spa water
  • Can use the spa almost immediately, unlike with chlorine
  • No odor, gentle on spa covers


THE BOTTOM LINE: If you are not using bromine tablets to sanitize, but instead using minerals and ozone, DiChlor may be a better shock to use, but – if you use Bromine tablets or Angel Tabs to sanitize, use the MPS shock to oxidize. I’ve always used bromine tablets and shock the spa with MPS after we use it. However, I also keep some DiChlor on hand, and give the spa a super shock about every month.


Happy Hot Tubbin’

Daniel Lara
Hot Tub Works