From what I've gathered on this site, it seems the chlorine should only be decreased by sunlight and attacking organic materials in the water.
So, if I have clean water and no sunlight, should my chlorine levels be stable (such that I should not have to add chlorine)?
This question is stemming from my hot tub. The hot tub is constantly covered when not in use and I'm wondering if I should be able to just let it sit without having to add chlorine if it is not used (even for weeks at a time). It seems logical, but is not the case - so I'm wondering if the logical conclusion is that I do have organics in the water -- but it would seem they would all be killed off after days of adding chlorine and no use of the tub and I'd eventually get to equilibrium.
BTW, I understand that 'sunlight' really means UV light - important to note since many pools and hot tubs are now using UV Sanitizers as the latest way to keeping your water clean. My hot tub does have a UV Sanitizer but I've disabled it.
Actually, that's another interesting question: Does anyone think that UV sanitizers kill different bacteria or kill it more efficiently? In other words, are they worth having in a pool or not? I did read on this forum that having one with a SWG makes sense since the SWG can replace the zapped chlorine - but does that just mean the SWG makes running one less painful or that having one really does help water purity?
Thanks for any insights.