borax in the pool

[chem geek]

If your CH wasn't low (since it's a vinyl pool), what you describe sounds like calcium carbonate over-saturation where adding acid clears that up, but that's not what this is since the CH is low.

Cloudiness usually comes from 3 sources -- over-saturation of calcium carbonate, the beginnings of an algae bloom, poor filtration of suspended particles.

When you add Borax, the pH goes up so if you are near saturation of calcium carbonate, that would make things cloudy locally, but then adding acid would restore the pH and things would clear up. With your low CH, I wouldn't expect there to be a lot of such cloudiness. It sounds like even after the pH is balanced you still have particles remaining. I can't explain that unless there was some sort of additive in the 20 Mule Team Borax, which there shouldn't be.

Is there no CYA in the water because this is an indoor pool? You didn't report that number. That just makes the 2 ppm FC be about 20 times stronger in disinfecting chlorine than a typical outdoor pool. It's a totally separate issue and I don't think it's related to the cloudiness, but I thought I'd mention it. If you find that your swimsuits degrade more rapidly (the elastic wears out faster) or if your skin and hair dry out (flaky or brittle), then you can consider adding a small amount of CYA to the water -- 10-20 ppm -- but I wouldn't do that now since you've already got a cloudiness issue (if you used Dichlor instead of pure CYA then it should dissolve readily and not contribute to cloudiness -- you'd have to add Dichlor over an extended period of time as your source of chlorine; alternatively, you could pre-dissolve pure CYA in water to ensure it wasn't cloudy before adding it).

So unfortunately I don't have a good answer for you. I will say that I recently had a problem with an oil film on the surface of my water that probably came from suntan lotion from daily pool use and that neither a scum ball nor enzymes seemed to handle it. In the past, I would shock the pool (with chlorine) and that would clear things up, but since my wife was using the pool every day I didn't want to do that. So instead I used non-chlorine shock (MPS) twice and that cleared things up rather quickly -- after first use the oil "slick" broke up into small pieces and after the second use it went away completely. If the cloudiness is due to some sort of organics that don't break down readily or quickly enough with normal chlorine levels, then you can try adding non-chlorine shock to see if that does the trick. An indoor pool has more of a tendency to build up combined chlorines and other organics because there is no sunlight to speed up their breakdown. Try the non-chlorine shock (MPS) and let us know if that works. It won't cause any harm (it's just costly, but for infrequent use it's not so bad).

Richard