Drain from the wall/bottom outlets only?

[chulinet]

I need to drain quite a lot water from my pool to reduce CYA accumulated by the chlorine tablets, yet it seems that I cannot drain from the wall/bottom outlets only. The attached photo shows the pipes, with the labels added after some experiments by myself. I can turn off one skimmer, but not both. Do I miss anything? If not, do I have to put a plug into each of the skimmer holes? Thanks so much for any help!

 

[mknauss]

Welcome to the forum!
It is not recommended to use your pool pump to drain/exchange water in your pool. If you lose prime, you can burn up your pump.
Get a submersible pump. If it is safe in your area to drain a pool, then you can rent one from Home Depot and be done in a few hours. If your water table is high and you should not drain your pool, then get a 1/2 hp sump pump from Amazon or Harbor Freight and do a no-drain water exchange.
Read Draining - Further Reading
What test results are you going by that says you need to drain your pool?
I suggest you read ABC's of Pool Water Chemistry.

 

[chulinet]

Thanks for the prompt reply and suggestions!
I have a plaster pool, and the CYA was 100+ a couple of weeks ago. Since I can only discharge some water before air gets in from the skimmers, the CYA is still more than 70 despite quite a few dilution efforts.

 

[mknauss]

How did you get those test results?

 

[chulinet]

My local Leslie stores tested the water for me. The results sound skeptical to me, though. CYA fluctuated from 100+ to less than 40 after a couple of dilutions, yet jumped to 70+ after more dilutions and shocks with Leslie's power powder pro, which is supposed to have no CYA. I also tried liquid chlorine to shock the water.

 

[mknauss]

I would not trust a Leslies pool store test for anything.

I suggest you get your own test kit. See Test Kits Compared. I suggest the TF-100 A proper test kit is needed to get the accurate water chemistry results needed to follow the TFP protocols.

 

[chulinet]

Thank you Marty. I will get my own test kit as you suggested!