Hello, gang. I found this forum mentioned in another pool care forum and thought I'd join up to absorb all the great information.
I have a 20,000 gallon solar-heated in-ground plaster/gunite pool and I can't keep my chlorine levels up. At the suggestion of the forums, I checked my CYA and found it to be above 150. I didn't realize my exclusive use of dichlor and trichlor for the past few years was going to drive that up nor did I understand the ramifications. I've stopped using the solid chlorines, bought a bunch of bleach and am installing a SWG in the next couple of weeks. In the meantime, I'd like to get everything back in order. As of this morning, here are my numbers:
Water temperature: 85 on average
The reason I've left my FC so low is that I've been draining the pool water into my yard to water the lawn and the plants (they're surviving it, so far) in lieu of running the sprinklers. The CYA number came from a test strip, so take it with a grain of salt. It may not be precise, but I'm pretty sure it's accurate in saying, "way too high."
So, what would be the best course of action at this point?
A. Drain the pool down and then refill it. How much do I need to drain? What are the risks (hydrostatic pressure, water table, etc.)?
B. Drain down a couple of inches and then refill repeatedly/continuous drain-refill? This wastes more water as I'm sure I'll be draining some of the fresh water in the process.
C. Live with it high while keeping FC suitably cranked up until the CYA comes down on its own due to normal water replacement for evaporation, splashing, bathers, etc? Will the SWG (Aquarite) be able to keep up or is that too much "strain" on it. I can supplement it with liquid chlorine, if needed, right?
D. We're most likely going to have the plaster resurfaced this fall after the swim season, which will require a full drain anyway. How does that affect what I should do now?
When draining, the local officials don't want it going into the storm drains due to pool water typically being high in chlorine and copper. However, mine's pretty clean of those things. I can drain into the sanitary sewer (preferred by the officials), but using to water my yard seems to be the least wasteful thing to do as long as the water is "clean" enough to not kill the plants and lawn. If I raise the chlorine to where I suspect you will suggest, it's off to the sewer for my draining.
As can be expected, I have a little bit of green algae that I've been brushing off. I run the filter pump 12 hours a day. It's a cartridge filter.
Thank you in advance for your advice!