I came across the site looking for answers on what to do about my high level of CYA and how to prepare my pool chemistry for closing. I wish that I had not waited until pool closing time to learn about the TFPC methods!
I just started noticing that the stabilizer number at the bottom of my test strip seems to be way up in the dark pink/purple high range somewhere between 150-300 ppm. Before now I had pretty much ignored this test because it had always seemed just fine and I had never learned about the pitfalls of CYA. I’m not sure when it actually started being out of range. I had no idea there was any concern about CYA levels. I’ve done lots of reading about CYA on this site for the last two days.
Knowing what TFP has taught me, I’ve shut off my chlorinator and removed all of the chlorine tablets. By doing this I also learned that the screen at the bottom of the chlorinator was very clogged, which would at least partially explain why I’ve been having a hard time the last few weeks keeping my chlorine level up. I had been resorting to using granular shock more often, which now I know was making my CYA even worse. I ordered the TF-100 test kit today. In the meantime I took a water sample to the pool store and got these test results:
FC = 0
CC = 0
PH = 7.0
TA = 110
CH = 210
CYA = 225
Pool store recommended that I add 2 gallons of 12.5% liquid chlorine (which I’ve now done) and use another gallon each weekend until I’m ready to close my pool, at which time I should come back in for another water sample to be advised again before closing. I had been going to this pool store every few weeks all year, but learned that they never wrote down my CYA level in their test records. No wonder I was oblivious to this issue. I guess you get what you pay for when it’s “free” sample testing. Also, several hours before adding the liquid chlorine, I also decided to brush my pool and add some algaecide and clarifier, thinking that will lower my chance of having an algae problem get started. Water looks clear and no signs of a problem. In fact, over the last two years I've never had an algae problem and have pretty much always had clear water.
This will be my first time closing my pool and now I’m confused on what my order of operations and timing of events should be to deal with my CYA issue and also to properly close my pool within the next few weeks. I’m hearing that before closing I need to shock, or I guess SLAM now, but it seems like that will not be practical to do at my high CYA levels. I was planning to lower the water below my skimmer anyway, but the Pool Math is showing I need to lower around 80%. Pool store said I should lower down to about 1 foot of water and refill. The other trick is that in order to discharge my water to the sewer drain (my only viable location for this much water) I need the chlorine level to be zero per my city regulations. Lastly, the pool store is saying (in general to all customers) not to close until the water temperature is 50 deg. F if using a mesh style safety cover (that’s me) or 60 deg. F if using a solid cover (not me). I'm likely going to need to wait 3 weeks for my temperature to drop, so during that time do I continue using liquid chlorine?
I'm having trouble figuring out which way to go with all of these variables. I would really appreciate some TFP advice.