Calcium creeping up even after a partial drain, what am I missing

Started by Karen Delgado · · 2 replies
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#1
Drained about a third of the pool in March to get ahead of it, fill water here runs 400 plus straight out of the hose so I knew it would climb back. CH was sitting around 480 before the drain, figured I'd buy myself a season. Tested last week and it's already back up near 600. No new leaks, no plaster issue I can see, tile line isn't scaling any worse than usual.

Only thing I can think of is evaporation doing the concentrating faster than I'm accounting for, this heat does not quit. Anyone actually run the numbers on how much a bigger drain buys you out here versus just chasing it with partials all summer. Not interested in a scale remover pitch, just trying to figure out if I'm draining wrong or draining too little.

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#2
How much water you actually losing a week to evaporation versus topping off, have you measured that or just guessing. Because at 400 fill water a third drain barely moves the needle if you're topping off 2-3 inches a week in this heat, that's concentrating CH right back up fast. Bucket test would tell you real evap loss, then you'd know if partials even make sense or if you need a bigger drain to get ahead of the math.
#3
Ray's math is right, a third drain against 400 fill water just doesn't have the runway you'd want if evap is doing real work on top of that. I don't deal with this since my fill water is nowhere near that hard, but the concentrating effect is the same logic as CYA creeping up from evap alone, I watch mine do it between my weekly tests even with basically zero splashout from the screen enclosure. If you haven't bucket tested, do that before deciding on drain size, guessing at evap loss here is going to throw your numbers off either way.