Anything I need to know about water chemistry in cooler weather?

J Pesaro

Member
Jun 7, 2022
8
Spartanburg, SC
Pool Size
25000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-15)
We are just completing our first summer as pool owners. I have (almost) learned how to read my Taylor test kit results, although still not at all confident with the CYA test, and have a question on the ALK. I have recently seen posts somewhere about LSI and “aggressive“ water in colder weather, and since I am not sure what it all means (and not sure I WANT to know in great detail), it is making me nervous. We have been diligent and lucky, and our water has been balanced and clear all summer. I have noticed in past couple of weeks that PH seems to be going up faster than it was after adding MA. Does temp have any effect on that? I do know that our salt cell will stop producing chlorine at a certain temp and that I will need to add liquid chlorine when that happens.

Here are my test results from this morning:

Water temp - 72
FC - 5.8
CC - 0
PH - 7.7
ALK - 70-80?? Turns pink at 7 drops but deeper red after 8 - which do I use?
CH - 60 (vinyl liner pool and wonder if this is more important in winter?)
CYA - 50??? *I think???* So, this test is killing me. Last pool store test showed 64 and that was around the first of July. We haven’t had much rain, so only backwashing of sand filter and occasional topping off water level has occurred, so maybe my number is close to accurate?

We are in upstate SC and are not planning on covering/closing our pool. We do have a new Generac whole house generator in case of a power failure so we can keep pump running if we dip below freezing. I just want to make sure I don’t mess things up as temps and water cool down.

Thanks in advance for any advice!
 
The end point of the TA test is when there is no further change so your ta is likely 80 so long as no further change occurred with drop #9
 
CSI/LSI and aggressive water is not applicable to vinyl pools. It is for plaster surfaces.

Okay, thanks. I was thinking I had read someplace that the CH number might matter in vinyl pools when water gets colder because of its effect on pool equipment or something. if it doesn’t, that’s great.
 
Okay, thanks. I was thinking I had read someplace that the CH number might matter in vinyl pools when water gets colder because of its effect on pool equipment or something. if it doesn’t, that’s great.

It does not.
 
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