Trying to reduce water evaporation - need help on pool covers (and everything else :)

[BJza]

Hi all


I'm new here, and I'm new to pools.


Having recently moved into a rental home in Cape Town (South Africa) with a pool, I've discovered that we're running out of water in the pool (4m x 10m x ~1.5m) fairly quickly, like maybe 1cm every week? Cape Town is currently experiencing water restrictions (so it's difficult to top up a pool using municipal water).


I have a yellow tarp that the landlord calls a "pool cover" but I have my doubts as to its effectiveness or its qualifications as a proper "pool cover" (I might be wrong though). My main concerns are that when I cover the pool (as evenly as I can), it drapes in the middle over the pool water, making contact, and puddles of water are appearing on top of the tarp.


My naive guess is that there shouldn't be water getting through the tarp but there's a part of me thinking maybe this is normal with other pool covers and it's by design (for some reason that escapes my understanding)?


So if I have to phrase this as a question, here you go:

• does a generic plastic sheet / tarp serve any useful purpose in preventing evaporation?
• should the sheet be in as little contact as possible with the water surface?
• is it normal to have significant puddles of water forming on top of the plastic sheet?

I have included a photo here for anyone that wants to see a little bit more of what I mean ... sorry it's a bit dim during dusk here ...


https://photos.app.goo.gl/SaXQ2pj1cPfTizmL9


I would sincerely appreciate any guidance or advice on the situation I'm experiencing with the existing "pool cover" and whether this is perfectly normal or if I should be considering something else? We have only started using the pool cover as of two days ago so it's too soon to tell what impact it's having on the water evaporation but I can't really afford to lose much more water before the water level drops below the skimmer space (I think that's what you call it).

 

[mknauss]

Welcome to the forum! :handshake:

Evaporation is an issue with pools. I do not know your climate but here in the desert of the USA we can lose up to 1" per day.

A cover will definitely reduce evaporation. But the one you show appears to be porous. The cover cannot be porous. There should not be pool water on top of the cover.

You do need to remove the cover every other day or so to let your water 'breathe'. Most evaporation occurs at night (warmer water versus air temperature).

I suggest you read Pool School - ABCs of Pool Water Chemistry and consider reviewing the entire Trouble Free Pool School book.

 

[Rollercoastr]

So if I have to phrase this as a question, here you go:

• does a generic plastic sheet / tarp serve any useful purpose in preventing evaporation?
• should the sheet be in as little contact as possible with the water surface?
• is it normal to have significant puddles of water forming on top of the plastic sheet?

Welcome BJza! 1 cm per week... That strikes me as such a low level of loss that I almost wonder if that's a typo?

My pool cover is basically a 2 big sheets of thick bubble wrap seamed together with waterproof tape and cut to the shape of the pool.

To answer your questions directly:

• Mine floats on the surface, essentially stopping evaporation. Your cover is sinking, so it's serving very little purpose
• No. Some covers that deploy automatically or serve a purpose of safety might be suspended over the water, but simple covers like mine float on the surface.
• See answer #1

It also looks as though that current "cover" is a lot of work! If I were you, I'd look for a new/better cover asap.

 

[jatkinson]

This an option??????

https://www.youtube.com/watch?v=rERRP-ESt7c