Quote Originally Posted by Teapot View Post
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.