TL;DR: Pool green on return from vacay, managed to get FC very high by mistake, CYA very low, what to do?
So I returned from a 12-day vacay to a green pool. Prior to leaving, I cleaned and brushed the pool, emptied out the skimmers and the pool vac bag, and raised FC to shock levels (24ppm for my 30kgal pool, stupidly assuming CYA was 60 as it has been for months). 7-days in, wifey called me and said the pool looked blue, but the pump was noisier than usual. I suspected the water level had dropped below the skimmers (she wasn't sure about that) and figured that some rain that was expected would address the noise issue.
Fast forward a few days, and as I'm arriving into town, I get a text that the pool turned green a couple of days before. When I arrived home, I noticed the pool was green but relatively clear (you could see the bottom). There were a lot of leaves at the bottom of the pool, and the pool vacuum quick disconnect had come loose. I assumed these two observations were the source of the problem and set to work.
- I first emptied the skimmer baskets which were chock full, scooped up leaves from the bottom of the pool, and noticed the pump was noisy and the filter pressure drop was well under 10psi (vs. the usual 15).
- I thought I'd check the pump strainer basket, and lo and behold, there was the source of the noise my wife had heard. I cleaned and reassembled the strainer basket, and pressure was back up to 15psi.
- I then (stupidly) assumed FC was zero and added 8gal of 10% liquid chlorine to bring FC to 24 (stupidly assuming CYA was at 60).
- After 6hrs, I replaced the quick disconnect on the pool vac (the old one had gone crumbly, presumably due to high FC) and let the pool vac run.
- At this time, I thought I'd test the pool to see if I needed to add more chlorine before going to bed. To my surprise, FC was 35ppm!!! I then tested CYA which appeared to be 20ppm or lower, which is the lowest I've ever seen. That sort of explained the high FC - perhaps FC was not quite 0 despite the pool being green. CH came back at 225ppm, and TA was 90ppm (TA test didn't turn red from green but rather yellow from blue, confirming high FC - a first for me).
Thanks for reading the above. Now for my questions:
- Should I intervene to lower the FC to 10ppm or is it OK let it drift down naturally?
- Should I bother to raise CYA to 30-40, or leave it at 20 or whatever lower number it's at?
- Should I worry about raising CH to 250?
- Does the cooler winter weather (I'm in Houston TX) have anything to do with the above observations, or is it irrelevant?
Thanks in advance for your responses!
Sent from my iPhone using Tapatalk