SWG output cover on/off

[rthorntn]

Hi,

Apologies if this has been asked before, I just got a 500 micron solar pool cover installed after a decade of making do without a cover.

So in the last decade, with a lot of help from TFP, I've mostly kept the water quality correct.

It's off-season here and so the pool cover will be on for a bit, I know I have to lower my SWG output, is there a general rule of thumb to get started with?

Say I used to run my SWG at 100% for 4 hours a day without a cover, should I drop it to say 50% or 25% or lower?

Obviously I'll be measuring chlorine with my FAS-DPD kit but I'm just trying to figure out where to start.

Thanks for looking.

Cheers
Richard

 

[jmastron]

My SWCG runtime with cover on all day is roughly 50% of what I need with the cover off, but that does vary through the season. Things that can affect that are CYA level, water temperature, sun angle, cloudy days, whether people are using the pool heavily when the cover's off, etc. Keep notes and over time you'll know what to set it to each time you have the cover on vs off. Note that it only affects FC usage if the cover's on while the sun is out (which is often the case here during the season because we don't use the pool most days). If you're covering overnight but taking it off in the morning that counts as a "cover off" day. The good thing is that FC can be within a pretty wide range, so you can adjust over a few days -- better to set a bit on the high side and lower it as needed.

That reminds me that I need to go test mine now; it's the other off-season here; cover's off but the water temps and amount of sun in the sky and on the pool is going down each day, so I have to keep lowering the runtime to match.