Chlorine level OK?

[kelemvor]

I've been trying to keep my chlorine level roughly 8-12 based on my cya level of 60ppm and the best guess chart. I'm also on a SWCG. I'm still trying to get the swcg dialed in now that I started using a solar cover and am losing less chlorine (hence the swing).

I haven't had any problems with algae to speak of but I'm continually reading posts where folks are trying to keep their cl at 2 or 3 with a swcg. Should I be thinking about reducing my chlorine levels?


One more thing, I usually put a couple oz of polyquat into the pool every few weeks. I recently read a few posts stating that chlorine will eat the polyquat. Should I just skip the stuff, or is it worthwhile?


I haven't had any algae problems at all with what I'm doing now, I was just thinking perhaps I could improve the feel of the water some?

[PoolDoc]

You can probably improve your water more by adding borax, but that's pretty subjective and not everyone notices the difference.

Personally, I'd try to do what was needed with chlorine, and maybe borax, and leave the polyquat alone unless I really needed it. Borax is stable in pools; polyquat, for several reasons, is not.

Keep in mind that the general principle of BBB pool care is "Do what you need, and add what you need, and nothing else". Attempting to 'perfect' pool chemistry causes no end of pool problems. So, if you've got problem, fix it. But if not, leave it alone.

Ben

[CarlD]

Why CYA level does your SWCG manual recommend? You should be there. Frequently, it seems to be higher than 60ppm, more like 80ppm.
Next, the best guess table has that level of FC for CYA of 100 or more, not for CYA of 60, and those are level for NON-SWCG pools.
Unless you have an algae problem you should probably be letting your SWCG make your chlorine and keep it at the 3-5 level or lower. Here the SWCG experts will hopefully chime in and give you the exact level--it may be even lower. The reason is that a properly functioning SWCG keeps a very consistent chlorine level in the pool.

Carl

[chem geek]

Don't go below an FC that is 5% of the CYA level with an SWCG. So if you are really at 60 ppm, don't go below 3 ppm. If you're at 80 ppm, don't go below 4 ppm FC. You risk getting algae if you go too low and it won't necessarily be visible but will instead look like an insatiable chlorine demand where you have to increase your SWCG on-time as it is just barely able to keep up with killing nascent not-yet-visible algae. This is where the myth of high phosphate levels "eating" chlorine or preventing SWCGs from outputting chlorine came from -- it's just nascent algae growth that is as fast as the relatively slow rate of chlorine introduction from an SWCG. Having the FC/CYA ratio be high enough to kill algae faster than it can grow is the answer; hence the 5% recommendation (for a sustained level; if you've already got nascent algae growth, then shocking would be needed to get ahead of such growth first).

[CarlD]

FC 5% of CYA level. GREAT Rule-of-Thumb rule, Richard!

Carl