Cya lowering plan -does this sound right ?

[Jsf721]

I purchased a submersible pump. It moves about 1000 gallons per hour at 8 feet lift. My pool is 36000 gallons.

My garden hose can fill my pool 1” per hour.

My plan it to shut pump. Drop level 12” pulling from 8 feet down in the deep end. And refill from the top of the shallow end.

When I wake up for work I hope to have it at a level so the pump can run for the day. And I’ll top of Friday night. If it’s below skimmers how bad it not to still a day without filtering and chlorinating ? My FC is at about 12 currently. Cya could be between 70-100. I get my sample an arms length down. (2.5 feet). I know cya is higher in deepest parts of pool.

Any other suggestions.

 

[Texas Splash]

If you need to leave the pump off for a few hours it will be fine. Your FC is high enough. Once the CYA gets down to the 60-70 range you could call it quits and live with it, but if you wish to bring the CYA down to 50 or so that's fine too.

 

[Jsf721]

If you need to leave the pump off for a few hours it will be fine. Your FC is high enough. Once the CYA gets down to the 60-70 range you could call it quits and live with it, but if you wish to bring the CYA down to 50 or so that's fine too.

Any idea how many inches of water or gallons in a 36k pool equate to a 10 ppm drop in cya ?
20x40 pool average depth is 4.5 feet (guess)

Thanks

 

[Rancho Cost-a-Lotta]

The area of your 20'x40' pool is 800 sq. ft. There are 7.48 gallons in a cubic foot (this adds depth to the equation). 800 sq ft x 7.48 gallons=5,984 gallons. So each foot equals about 6000 gallons, or 500 gallons per inch.

Draining one foot of water equates to about 16.6% of your pool's volume which is equal to the reduction in CYA.

 

[Texas Splash]

Thanks Mike! (@Rancho Cost-a-Lotta) My head was about to burst on that one.