Didn't realize how fast the spa evaporates compared to the pool

Started by Karen Delgado · · 4 replies
Back to the forum
Reply
#1
Been tracking water levels for the calcium post I made last week and noticed the spa drops almost as much overnight as the whole pool does, despite being a fraction of the gallons. Surface area to volume ratio I guess, plus mine sits higher up and catches more wind. Add the jets running and it's basically a fountain for evaporation. Explains why my spa calcium and TDS climb faster than the pool ever does, less water to concentrate the same minerals into. Been topping it off more between fills now instead of waiting for the auto-fill to catch it. Anybody else notice their spa needs way more makeup water than math would suggest just going by size.

4 Replies

#2
Karen youre spot on about the surface area thing, ours is attached to the pool but spillover style and I swear the spa water level drops way more than the math shoudl suggest just going by gallons. One thing that gets left out though is the heat, we run ours warmer than pool temp obviously and that alone speeds up evaporation on top of the wind and surface ratio stuff. Between that and my kids treating it like a hot tub jacuzzi with jets cranked the whole time im topping it off almost every few days now, anyway.
#3
Dana's right about the heat but nobody's mentioning the desert air itself doing most the work. My spa's not even attached and it drops close to an inch overnight, pool barely moves half that for way more surface area total. Hot water plus bone dry air plus wind just strips it, jets cranked only makes it worse by throwing droplets up where they flash off instant.

Only thing that helped me was quitting the daily top off obsession and just accepting the spa needs its own fill schedule separate from the pool math. Chasing it every night is how you end up overdosing calcium trying to compensate for water that's gonna leave again by morning anyway.
#4
ray's onto something with the dry air but i think theres a splash factor too that nobody mentioned, i dont even have a spa, just the pool, but my old cracked deck around the equipment pad used to pull water out slow through a hairline leak and it took me forever to tell that apart from just evaporation. point is if any of you have jets or spillover going hard enough to throw water past the coping onto the deck, thats not evaporation loss going into your calcium math at all, thats just gone. splashout looks identical to evaporation on a water level stick.

so before assuming its 100% desert air stripping it, worth checking if some of that nightly drop is landing on your deck instead of the sky. would explain why topping off nightly never seems to catch up, youre topping off actual lost water plus water that shouldnt count as "concentrating minerals" in the first place.
#5
Actually swamp_tyler mentioning splashout hit home, we had a stretch where the kids were cannonballing right at the spillover edge and I was topping off like crazy blaming the desert air when really half that water was just sitting on my deck getting the coping wet, felt dumb once I noticed the wet patch every morning. Anyway once I moved cannonball time away from that edge my top offs dropped by half so worth checking your deck before you assume its all evaporation.