OK - So I'm draining 1/2 my pool and refilling today. Next?

sws1

Member
Aug 13, 2010
23
Had very high CYA and CH numbers due to Trichlor / CalHypo regimen. Water is otherwise spotless.

SO, draining roughly half and refilling today / tomorrow with water from hose. And then moving to a liquid chlorine regime (maybe with some algeacide / clarifier as well since I have so much of it.)

Will I need to shock after I fill it up with tap water? Or can I simply adjust to my desired chemistry and let her go?

I know certainly that if I keep my chlorine in desired range, I won't need to shock each week like I did before. If that's true, then when I have a big party / heavy rain, etc, I should just add more liquid chlorine in advance????
 

JohnT

Admin
Mod Squad
TFP Expert
Apr 4, 2007
9,475
SW Indiana
You probably won't need to shock unless you let your chlorine level stay low for too long during the process. You can add some liquid chlorine and allow the water from the hose to mix it into the water as you fill.

If I have a large bather load, I usually nudge my FC up about 2ppm before hand, then push it back up 4 or 5ppm after everyone is done swimming and keep a little closer eye on the chlorine level for the next day or so to see how the pool is dealing with it.
 

sws1

Member
Aug 13, 2010
23
Thanks.
My FC before draining was roughly 12 or 13, because CYA was so high. Assuming I'm simply diluting, the FC should go to 6.5 and the CYA to 60 or 70 (I hope). If I understand correctly, the level will be perfectly ok and no shock. Of course, I'll test to be sure.
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
20,799
San Dimas, CA (LA County)
sws1 said:
Thanks.
My FC before draining was roughly 12 or 13, because CYA was so high. Assuming I'm simply diluting, the FC should go to 6.5 and the CYA to 60 or 70 (I hope). If I understand correctly, the level will be perfectly ok and no shock. Of course, I'll test to be sure.
Test your fill water. Then you'll know what to expect. Some water companies use chloramines to disinfect - you'll see that as CC. Or the fill water may be really hard; you can add some acid as you fill and let the hose blast mix it all in. I'd probably add a couple PPM of chlorine right from the get-go. The water will have to circulate for a day or so before you can get your next set of results, and it's cheap insurance.
 

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