New to TFP, but been reading through threads and wishing I'd developed this obsession a few years ago.
We have a 35,000 gal in-ground plaster pool built in around '74. We bought the house in foreclosure in 2008, and while the pool was clear when we bought it, that was courtesy of the bank doing just enough to get through the sale process, and we weren't really sure we were going to keep the pool. We kept it clear for the first summer by keeping the chlorine levels high, and quickly learned that the plaster probably had not been resurfaced since the 80's at the latest. We ended up letting it go fallow, throwing mosquito ducks and just enough bleach to prevent a mosquito outbreak, and keeping just enough water in it to prevent it from popping out of the ground. We resurfaced in 2010, with a low-bid supplier who'd done other work in the area and came recommended. Pool didn't get a lot of use after the resurfacing until last summer, for a number of reasons unrelated to the pool itself.
Maintenance has been half-a**ed by yours truly, mostly tri-chlor tabs and granular chlorine (di-chlor), testing with the "traditional" 4-in-1 kit to ensure that pH is balanced and intermittently testing chlorine levels (every few weeks, mostly just to determine whether to throw in some more chlorine). And the occasional copper-based algicide to deal with algae blooms. This year I finally invested in a solar cover, primarily to reduce evaporation in the current drought, but it's had the byproduct of being extraordinarily effective at raising the pool temp - after the first week it was on, temps were breaking 90 degrees. My younger hates to be cold (zero body fat), but loves swimming, and a 90 degree pool is her ideal, so the pool's seeing use, which in turn made me pay more attention to maintenance. This brings us to our current situation.
Issue 1: algae spots
We have some limited areas of algae - not enough to cloud the water significantly but it's there. And I've come to realize that my typical approach of ****-load of chlorine and some copper algicide isn't fixing the problem, just keeping it in check. And after some reading here, I realize I've created as many problems as I've solved.
Issue 2: difficulty maintaining chlorine levels
Now that I'm paying attention, I'm seeing the chlorine levels drop rather quickly. It wasn't entirely surprising (warm temps, full sun, mild algae issue) - but the rate of change seemed too high. So I ordered the K-2006 kit so I could get a more accurate picture of the state of affairs. Kit arrived last night. Tested pH, FC, CC, and CYA. FC is after adding 2 gal 12.5% chlorine Monday morning.
pH - 7.4
FC < .5
CC < .5
CYA > 100 (this is where I stopped testing and started drinking, as the idea of even a partial drain/refill is ugly in the current drought. So didn't test TA or CH)
Issue 3: popped / missing waterline tiles
I mention this issue primarily as I know the popped tiles can be a good hiding place for algae, and I'm curious if the missing tiles can be impacting pool chemistry at all.
So...the grand dilemma is this - to address issue 1, I really need to SLAM, but that would require addressing issue 2. And as far as I can see, the big solution for issue 2 is a partial to 2/3rd drain and refill. However, my current water allocation from the water district is < 200 gallons per day, which is low for a family of 4 with teenage / tween girls. Assuming NO other water use, we're talking about 3 months worth of water to replace 18,000 gal...which realistically might not be enough to get to ideal numbers, but could be enough to get me to a more manageable level.
Any recommendations would be appreciated.