I have a Sundance 1998 Cameo. Recently, the two speed pump stopped circulating water. On inspection, I found what I think to be a faulty check valve located immediately under the diverter valve for the whirlpool/intelli-jets.

I found a small (1.5 inch?) in diameter disk with rubber on the edges free floating in the check valve. I'm guessing it was once attached and broke free. In the position I first found it, it was blocking circulation. When I flipped it upside down, all but one jet works fine. I think this disk is larger than the hole for the diverter valve, and in any event, it is not possible to grab with anything I own. (It's about 14" down below the diverter valve surface.

What is this check valve for? Do I need to replace it if everything seems to be working well (except for one seat we never use)? Is there any harm in just leaving the detached part there?