Solar blanket & chlorine levels.

[PeterDM]

I always use a solar blanket as my pool does not have a heater. As it is only a 24' x 12' x 5' pool it heats up fairly quickly once the weather gets warm. Slammed the pool on opening, back in late May & got the water completely clear after a couple of weeks. Since then I have kept the solar blanket on night & day, only removing it for an hour or two max on days when we are using the pool. My chlorine usage has been surprisingly low - the FC level has been consistently around 5/6 adding only a very small quantity of liquid chlorine every evening - sometimes only every second evening.

The last three days I have left the solar blanket off the pool as the daytime temps have been in the 30's C & the water is as warm as I want it. However, the chlorine usage seems to have gone up dramatically in those 3 days & today I inadvertently allowed the FC to drop down to around 1 by the evening. I noticed slight algae growth on a few areas of the pool walls - amazing how little time it takes to get a hold.

In any case, I'm wondering if others have experienced this using solar blankets - it would appear (somewhat logically) that the solar blanket reduces the exposure of the FC to sunlight to a significant degree, minimizing the amount of chlorine required in the pool. I might add that my CYA level is very low (around 20) which probably leads to my pool being particularly sensitive to chlorine loss by sunlight.

 

[MSchutzer]

Yes, a solar blanket greatly reduces the daytime chlorine loss to UV. I keep my pool covered all the time except when swimming and my chlorine use (loss) is consistently 1 ppm/day. In addition to keeping the pool in the low 90’s (I also have solar but it’s off mostly this time of year) it cuts the chlorine use way down and reduces the evaporation loss to almost nothing.

The only downside is that they only last a year or two at most regardless of what they claim on the warrant.

 

[jmastron]

Absolutely -- a solar blanket on during the day reduces evaporation and FC loss significantly. I don't have an autofill so I can observe -- a week with the cover on and the level drops maybe 1/4"; a week with the cover off and it drops over an inch. Similarly, my FC loss with the cover on during the day is <1ppm, with the cover off 2-3ppm (and would be more at a lower CYA level).

I definitely have to remember to adjust the Stenner (previously) and SWCG (now) times when the cover is on vs off. We don't use the pool every day, so I don't take it off every day. Around here, there's even a water district rebate for a solar cover, presumably because some number of people leaving them on during the day (and at night to a lesser extent) reduces water use.

 

[PeterDM]

Thanks for the responses. Yes, this corresponds to my experience. Chlorine loss, heat loss & water loss all seem to be significantly reduced by using a solar blanket. The 3 days I left the cover off led to an unanticipated drop in FC that caused the appearance of a very slight amount of algae that I have been battling ever since. Lesson learned.

 

[Newdude]

Lesson learned.

It’s the conundrum of life. You can’t get the experience without flubbing it first. Maybe several times before you

Had you thought to ask, we coulda told you, but you have to know in the first place what to even ask. But HEY !!! Now you know and can be ready next time.