Pool covers (solar)

[FormerBromineUser]

Interesting info, ChemGeek! One part seems strange, though. Year after year with my auto-cover, I actually have to open it during the day in the hottest times of summer to cool the pool down. My water temps (when compared to cover on during the day vs off), tell me that cover-off will cool the water more than cover on. (Hope that makes sense). Maybe that's been a fluke.....

[JimK]

Interesting info, ChemGeek! One part seems strange, though. Year after year with my auto-cover, I actually have to open it during the day in the hottest times of summer to cool the pool down. My water temps (when compared to cover on during the day vs off), tell me that cover-off will cool the water more than cover on. (Hope that makes sense). Maybe that's been a fluke.....

Cover off = more evaporation = cooler water.

[Anonymous [GDPR] European in the UK]

Where abouts is your thermometer placed? many are just under the surface. As Chemgeek said the clear covers heat deeper into the pool warming the water whereas dark covers heat very close to the cover where the thermometers are. Try the test with the thermometer nearer the bottom of the pool for a better assessment. Getting into a pool with stratified water, warm on the top cold on the bottom isn't as pleasant as warm all the way through.

[FormerBromineUser]

Great point, Teapot... As usual!

[Toybuilder]

I'm hitchin' a ride. This is great information. Thanks for the post bssage.

[SunnyOptimism]

Does anyone have any links to threads regarding the use/efficacy of liquid chemical cover products like COVERFree? These would be any products that use hydrophobic fatty acids (eg, stearic acid) to create a monolayer film on the water's surface to reduce evaporation.

Like many users, I have an irregular shaped pool and it is just a royal pain to use the bubble solar covers. The one that I had (came with the pool) I only used a few times and it was more trouble than it was worth. It eventually got rolled up, put off in the corner of the yard and became a lizard habitat (and then attracted a rattle snake so I got rid of it). I have no intentions of purchasing one again and all of the other physical cover options (solar disks, etc) seem like just as much of an inconvenience.

The main thing I'm looking for is evaporation reduction; I don't care much about heat loss or gain. Specifically I'd like to read about anyone's real world experience with the products including any hard data that they might have on water loss.

Thank you.

[Anonymous [GDPR] European in the UK]

They work, they lower the evaporation in still water, i.e. when the pump is off.
When the pump is on, the monolayer is disturbed and when swimmers are in the pool that gunk of fatty acids (bacterial food, biofilm layer in waiting) it will coat the entire filter providing the ideal environment for growth of pathogens, usually the thing we are tying to avoid. In Europe the owners of the product change frequently and I have heard of court cases after the water went bad but the settlements have a gagging order attached so you don't find out much about them. We have enough problems with sun cream without adding it on purpose.

[SunnyOptimism]

They work, they lower the evaporation in still water, i.e. when the pump is off.
When the pump is on, the monolayer is disturbed and when swimmers are in the pool that gunk of fatty acids (bacterial food, biofilm layer in waiting) it will coat the entire filter providing the ideal environment for growth of pathogens, usually the thing we are tying to avoid. In Europe the owners of the product change frequently and I have heard of court cases after the water went bad but the settlements have a gagging order attached so you don't find out much about them. We have enough problems with sun cream without adding it on purpose.

Hi Teapot, thanks for the quick reply. Being in the UK, I guess my afternoon is your night :-)

Any links you might have on hand would be most appreciated but don't trouble yourself if you have to search them out.

In trying to understand your post a bit better, do you feel the added possibility of creating biofilms from the addition of these types of chemicals outweighs any benefit in water evaporation?

Here in the Southwest United States, municipal water is very expensive and our climate is quite dry. For example, in the driest months (May & Jun) the RH can be as low as 10% (fun weather facts - here). Suffice it to say, uncovered pools can lose a lot of water to evaporation. In terms of operations, my pool FC is maintained at normal sanitizing levels. I am quite fastidious about keeping the pool clean and the water chemistry balanced and, along with the typical schedule of filter backwashing (every 4-6 weeks), I tear down my DE filter and fully clean out all old DE and cartridges every season.

Thanks for any further thoughts you might have.

[Anonymous [GDPR] European in the UK]

Yes, some time difference, I heard on the UK news that a total water ban in California was it? I understand the issue, with non box/oval pools can you cut the normal cover in two to make it easier to manage? Rather do that than add the liquid cover.
No info I am afraid, expected some from a case in the UK but the gagging order prevented it. Just to extreme for me, I want water as pure and clean as I can get and a pool cover is vital during summer, it seriously reduces chemical and water usage but I know the conditions in parts of the USA are extreme to some of our weather.

[SunnyOptimism]

Yes, some time difference, I heard on the UK news that a total water ban in California was it? I understand the issue, with non box/oval pools can you cut the normal cover in two to make it easier to manage? Rather do that than add the liquid cover.

Luckily I live in the Copper State and not the Golden State!! Yes, Governor Brown issued an Executive Order that mandates the reduction of water use to levels 25% lower than 2013 values for all CA counties (farmers are excluded from the ban). Since the snow-pack in the Sierra Nevada mountain range is only at 5% depth of historic averages and it supplies most of CA with its fresh water, his order is reasonable. The net effect though is that most areas will have to cut back on landscape watering (unless that water is fed by grey-water systems) and folks will see higher water bills to "nudge" them to take shorter showers. Theoretically a code enforcement officer could write you a citation for washing your car in the driveway but that's probably not likely. I live in Arizona where we have lots of Colorado river water and deep aquifer wells. But AZ is almost always in a drought so we're quite use to high water bills. My landscaping is quite minimal (pretty close to Xeriscaping and artificial turf in the backyard), so my biggest water hogs are showers, toilet bowls, washing machines and.....the pool!

Cutting up bubble covers is not really desirable for me. Aside from the irregular shape of my pool, I have two water features (a spillway from the spa into the pool and a waterfall) and that tends to sink the covers. As well, I have almost no storage area for them so they wind up gathering wildlife when rolled up (scorpions are easy to kill but scare the pants off you when you accidentally run across them). I'm tempted to try the liquid cover chemical and try to do a before and after evaporation experiment with my autofill shut off to see how much the water loss is cut down under "normal" operating procedures (the water features run at least once per day). I don't think the "gunk" load would cause a huge hit to the filter and, even if it did, tearing down the filter is a 1/2 day project anyway.

Thanks for being a sounding board and I'll start a separate thread if/when I decide to experiment.

Cheers!