High temps eating chlorine?

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M

mrshanes

0
Apr 26, 2011
50
Morgantown, WV
Do high water temperatures cause chlorine to be used up quicker? My inground has been rather stable this year, but lately the chlorine has dipped rather low. With our auto safety cover on all the time, the SWG was only on 20% and it maintained the chlorine level around 6 without any problems. Lately, the chlorine level has been declining with each test (every few days). Yesterday evening it dipped to it's lowest of 2. I added about 80 oz of 6% bleach and turned the SWG up to 75% and let it run all night. This morning I tested and it was up to 3. With my CYA level, I like it to be around 5, so I'll be adding more bleach today to get it back up, but is it the heat that's causing this? The water has been around 91-93 degrees for the last two weeks which is really when it started the steady decline. I typically run the pump for 9 hours with the SWG at 20% and that was plenty. As I said it ran 9 hours yesterday and then I turned it back on last night at 11pm when I added the bleach and ran these tests this morning at 6:30.

FC: 3
CC: .5
TC: 3.5
pH: 7.2 (just recently dipped from 7.4 - I'll bring that back up later today also)
CH: 110
TA: 110
CYA: 75

Note: Our auto cover is closed unless we are in it, so it doesn't get much full sun.

Thanks
 
Survey says yes. Why, I don't know. Chlorine degrades faster in higher temperatures, even just sitting in the jug. Plus if there's anything growing in the pool, even tiny amounts you can't see, it will grow faster in the warmth. Below 50, algae hardly grows at all, but when it warms up, look out!
 
I'll pull the FC back up to 5 this evening and then do an overnight test to see what's going on. Sounds like I should either increase my pump time or increase the percentage on the SWG (or both) during periods when the water temp is high.
Thanks
 
hayabusa3 said:
any chance your bleach is old? Been storing it in the heat too long?
Click to expand...

I don't use bleach. I have a SWG. I only added some last night to bring it up to 3ppm because I was nervous with it being at 2. I'm buying fresh bleach today to bring it the rest of the way back up to 5 (or slightly higher). The bleach I added last night was several months old, but it's been stored in the house (not the heat).
 
On Friday evening I got the FC back up to 7 when I tested at 11pm. I tested the next morning at 6:30 and it was still 7, so I guess that means I'm OK. Checked the level again yesterday (Sunday) afternoon after being in the pool most of the day and the level was back down to 5. I added more bleach to get it back up. Should I need to be supplementing bleach if I have this SWG? Is it only because of the high temps lately? The water is still in the low 90s. I bumped the SWG up and increased my pump run time by an hour (10 hours now). Nobody will be in the pool today and the cover will be on all day. I'll check it this evening and see how the level is.
 
Something else is odd here. Is the SWG throwing any error codes during it's run time? With CYA at 75, you should not be losing FC with the SWG running, as long as it is properly sized and is in fact making chlorine :scratch:
 

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dmanb2b said:
Something else is odd here. Is the SWG throwing any error codes during it's run time? With CYA at 75, you should not be losing FC with the SWG running, as long as it is properly sized and is in fact making chlorine :scratch:
Click to expand...

I believe it's properly sized. It's the Aqua Rite SWG with the 40,000 gallon cell. I had to actually turn it way back earlier in the summer in order to get my chlorine down to a decent level. There are no error codes displayed and everything seems to be working fine. The cover was on all day yesterday and nobody was swimming. I checked last night around 8pm and the fc was 8, so it seemed to be OK. I'll continue to monitor the levels closely. I've been reading some posts on here about taking the cell out to clean and check to see if it's producing. I may do that if things continue to seem weird. But, it's only been in use for 3 months. Should it really need cleaned already?
 
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