So recently I went through a large drain/refill to get my CYA numbers down. Supposedly before the drain I had 150ppm (or more) CYA. Before drain I had 16078 gallons, and after draining I had 5032 gallons of original water left. Then I refilled back to the ~16k gallon mark. After the week of slowly refilling the pool with well water here was my test results (from the store):
saturation index 0
Adj TA 173
Tot hardness 256
Around this same time, another test from another store gave me a CYA of 40
I then shocked my pool to ~24ppm, and shocked again a day later to my guess of 12ppm. I haven't added any chemicals in the past week, just filtering as much as possible. Here are my current test results:
saturation index 0.9
Adj TA 178
Tot hardness 282
I was not expecting the CYA to jump up like that. I even had them test again (manually, instead of in the machine). Is there something like my relatively higher FC that could be affecting CYA to make it inaccurate? Or do I need to drain again?
I've attached some pictures of the pool...vinyl liner is very old and wrinkled, and concrete has seen better days. Also the skimmer line is leaking, so it is plugged off in the skimmer and disconnected from the pump, as you can see. Not sure what the 3rd tall PVC line is, maybe it's a winterizing line or something.
Big question is this: If my CYA is where I'm hoping it was, in the 40-60ppm range, then my FC is fine. But if my CYA is really that high at 119ppm, I'm going to have to go through the entire draining cycle again, which was a pain in the butt and a strain on my well.
Also, any other suggestions on what to adjust in my chemistry, and what order? I know pH is a little higher and hardness too.