opening and water replacement

sdtfp

Gold Supporter
Jun 4, 2020
60
NYC
This will be my first opening of the pool. Usually it opens two weeks memorial day so I am just planning things out now. Two things make this an odd opening and I wanted to ask how to handle them. First, I plan to replace 3/4 of the water as I have high CYA.. think it was like 130 last time I checked. Secondly, The pool pros closed it last season and that is when I realized the chlorine tab where a detriment to the CYA, so I told them no chlorine tabs. But I didn't over chlorinate and also I went all winter without chlorine tabs. I just added a bit of chlorine manually late fall when I realized my mistake. I checked the pool today and its still decently clear. But now the temp was in 70s yesterday and 60s today, so I probably need to add more chlorine before I can get to Mid may.

So when should I open and when should I replace the water? And should I be adding chlorine until then? I know chlorine needs to be added when filter is running, so I fear adding now before the filter is on and when temps are warm is going to do nothing. In hindsight, maybe I should have just added the chlorine tabs in the floater since I am goign to replace the water anyhow? Should I do that now? But that is not normal here, so i am still a bit confused on how the pool maintains chlorine until opening. I guess if I overchlorinate at closing, it would cover me until may? But that seems like a really long time considering 70s in late march. Or maybe this is just an abnormal spring and itll cool down again soon.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
24,658
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
It takes a while for your pool water to warm up above 60 where algae starts becoming a problem. The few warm days hardly change the water temperature of an inground pool. Also the ground is still cold.

I don’t expect water temperature above 60 until around May 1.

Check your CYA after opening your pool and running the pump for a few days. You may have lost more CYA over the winter then you think.
 

sdtfp

Gold Supporter
Jun 4, 2020
60
NYC
thanks I checked with an infrared thermometer and it war 46. I'll monitor it this way.