For spa sanitation, you can use chlorine, but why – when bromine is superior? Bromine has several advantages in a hot tub:
- More stable than chlorine at high temperatures
- More stable than chlorine in wider pH ranges
- Bromine has much less odor than chlorine
- Unlike chlorine, combined bromine is still effective
In using bromine, there is one small but important, and often misunderstood difference from chlorine.
BUILDING A BROMIDE BANK
To be effective, a residual of Bromides must be present, also known as a Bromide Bank, or Reserve. Notice that I said Bromide, not Bromine. Bromides are converted to Bromine in the presence of an oxidizer, such as spa shock, liquid chlorine, or ozone.
Bromine tablets are actually a mixture of chlorine and bromides. It can take several weeks for enough bromine tablets to dissolve, to build an effective level of bromides in the spa – so that bromine can be created. Each time you drain the spa, the bromide level drops to zero.
The best way to build a bromine bank is to add Sodium Bromide to your spa, each time you drain and refill. After building your Bromide Bank, shock the spa with your preferred oxidizer to activate the bromide ions, and convert them to hypobromous acid, the killing form of bromine.
2-Part and 3-Part Bromine Systems
A 2-Part Bromine system is basically adding Sodium Bromide (Step 1) and Shocking regularly (Step 2) to re-activate the Bromide ions into Bromine. A 3-Part system is also adding Bromine Tablets (Step 3) as a way to prevent gaps in sanitizing.
If you just add bromine tablets, without first adding Sodium Bromide, you will have trouble getting a good reading for Bromine levels in the spa, and the water could be unhealthy. Build a bromide bank first, of 10-15 ppm of Sodium Bromide, shock the spa, and then add a few tablets to a bromine floater to maintain a bromine residual of 3-5ppm (or 1-3ppm for Spas using mineral purifiers or ozonators).
HOW TO USE BROMINE IN HOT TUBS
In Summary, using Bromine in your spa or hot tub is best, but to be effective, there needs to be a good level of bromide ions in the water. Regular oxidation, or shocking is also important to convert the bromide into bromine. Use bromine tablets to more easily maintain a consistent bromine level.
- Add sodium bromide to your spa, following the label instructions, each time you drain and refill.
- Use spa shock after building your bromide bank, and weekly thereafter, to activate bromine.
- Use bromine tablets in a small floater, to help maintain bromide and bromine levels.
Happy Hot Tubbin’
Hot Tub Works