effect of solar cover on combined chorine

iam4iam

LifeTime Supporter
May 5, 2012
257
Johnson City, TN
I've been using a homemade "heat retention cover" (popularly known as "solar cover") and it has been doing its job rather well. My pool water hit 88 degrees the other day! The pool does get 12+ hours of sun during summer months, which obviously helps. I have toyed with whether to leave the cover on during the day or not, and since the plastic I used is "clear" (translucent actually), on a clear day the pool temp increases about as much with the cover left on as it does if I take it off. For this reason, I generally choose to leave the pool covered at all times unless someone wants to swim.

Today I did my weekly chlorine test and decided to measure CC just for kicks and giggles, which I hadn't done in awhile, since the water is clear and CC is always <0.5 when I measure it. I was surprised to find CC=1.0. Should I be concerned and SLAM the pool? The cover was left on today, and I'm wondering if the higher than normal CC could be because the chloramines weren't able to gas off with the pool covered.
 
I never had any noticeable CC buildup with my solar cover, and it is always on, unless swimming, or the pool gets too hot. Then it's left off overnight.

But, it does not cover all the pool, it's a 20 by 40 foot cover cut to size. Since the widest part of the pool is more than 20 feet, there is about 5% of the pool always uncovered.

Not sure if that relates to your problem, but if you do find CC goes down with the cover off, no reason it needs to be full sized. Maybe you can fold it back a bit as a test, and find a happy medium?
 
CC buildup is a common problem for pools that are left covered all of the time. It doesn't take all that much time with the cover off to avoid this problem, a few hours a week of sunlight with the cover off usually takes care of it.
 
Thank you, everyone, for helping to confirm my suspicion.
CC buildup is a common problem for pools that are left covered all of the time. It doesn't take all that much time with the cover off to avoid this problem, a few hours a week of sunlight with the cover off usually takes care of it.
Apparently it doesn't take all that much time to create the problem (if one considers CC=1 to be a "problem," which I do). The cover had only been on for around 24 hours. (Now it has been over 48 hours.) I meant to take another measurement at dusk this evening to see if the "problem" was even worse. I'll measure tomorrow morning before I remove the cover and then again at dusk tomorrow.
As an aside, I made the cover out of pvc and 3 rolls of 10'x25' 3 mil plastic from the hardware store. I built 8 frames approx. 8'x8' (four of them slightly smaller to account for corners of pool and pool ladder) out of the pvc and just taped the plastic to the frames. I can remove them by myself in about 10 minutes. I just lean them against the house and tie them down so the wind doesn't blow them over.
 
As an aside, I made the cover out of pvc and 3 rolls of 10'x25' 3 mil plastic from the hardware store. I built 8 frames approx. 8'x8' (four of them slightly smaller to account for corners of pool and pool ladder) out of the pvc and just taped the plastic to the frames. I can remove them by myself in about 10 minutes. I just lean them against the house and tie them down so the wind doesn't blow them over.
Interesting! Can we see a pic? :smile:
 
I took a water sample and then removed the cover(s), even though it is mostly overcast today. I just wanted to give the pool a chance to "air out" to remove chloramines. I wish I had tested the sample before I removed the covers, because I got a reading of CC=0, which, although I'm delighted to see, baffles me, since the cover had not been removed since the reading of CC=1 (total of about 60 hours)!

BTW, I've been meaing to post a pic of the cover(s), but I never got around to taking one. I'll take one and post it soon. Total cost was under $100 and at least half of that was the pvc, which is a one-time expense. Even if I have to replace the plastic every year, it's way less expensive than replacing a bubble cover, which, from what I understand, often only lasts a year. The plastic is "clear" (actually translucent) so a significant amount of heat from the sun passes through. Experimentation has revealed that heat gain during the day on a sunny day is about the same (or perhaps slightly greater due to factors like wind) with the cover on than with it off, while heat loss at night is about half of what it was without the cover. (I was a little disappointed, honestly, in the latter statistic. I was hoping for even better heat retention than that, but I'll take it.) In case you're wondering, my pool thermometer is 3 feet deep, so it's not measuring residual heat from the pool covers (which would be minimal anyway, since they're very light colored).
 

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I have a co-worker that is making something like that with Hula Hoops and plastic bags. He's NOT TFP receptive and is always coming to work and complaining about algae. Can't teach an old dog...
 
Well, we've had a few clear days in a row with air temps near 90o. I was wondering how high the pool water temperature would get with my insulators, since this is the warmest (and sunniest) stretch I think we've had since I made them. I left the "insulators" on today, just to test my theory that the heat from the sun does, indeed, penetrate them, and I've been checking the thermometer (which is 3 feet deep in the water) like I'm obsessed (which I am, obviously). It just read 90o, which is a record since I've been keeping track, and that includes two summers ago, when June was the hottest month on record in the area! I guess the heat from the sun does penetrate the insulators! I had the pool uncovered all day yesterday (in nearly identical weather conditions), and the water only heated up from 86o to 88o. There was only a slight breeze, but I'm guessing activity in the pool also contributed to the temperature increase of only 2o. I can't help but grin at thought of 90o poolwater in NE Tennessee at the end of August with no heater! :D
 
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