Hi
I'm worried I'm in the wrong place here but I really appreciate this forum and wanted to join and hopefully even contribute knowledge as I accumulate it. I work in the pool industry and I am currently working as a plantroom opperator at an indoor swim school just to bulk up my hours as a swim instructor/coach(no CYA).
We have UV and Ozone as secondary disinfection but they're not enough to consistent ennough to keep CCL down below 0.2ppm. A third party company does checks of the expensive automated dosing equipment we rent from them and gives us water quality advice monthly but have not advised us on how regularly to shock dose with chlorine or how to achieve this elusive <0.2 ppm CCL we aspire to achieve. So I started researching and found myself here. I'm hoping to not rely so heavily on this third party company so much and stretch the friendship.

So I have had to shock dose a couple of times, got information from questionable sources that recommended specific concentration of FCL to get the water to. I know this is wrong now and I add a bit more liquid chlorine than is required to achieve 10 x CCL. Often when I come back in the morning to retest CCL is not nearly as low as I expect it to be.

Recently the UV and Ozone both went off due to electrical problems and CCL ended up at 1.8ppm one night after classes. I added more than 10L of 12.5% liquid chlorine to this 75,000L pool to get FCL to roughly 20ppm. pH was 7.43, Alkalinity 113 (a bit high). I added some acid just to be safe making sure pH didn't go over 7.6. Still I came back in the morning and the reaction seemed incomplete when I got a reading of FCL 3.10, TCL 4.05, pH7.38, ALK 116. Any idea what went wrong there?

So I panick and don't want classes cancelled on my watch, go to the nearest pool store that was open at that early hour and get a non-chlorine shock. It was Sodium Carbonate Peroxyhydrate (sodium percarbonate). I even got on the phone to the third party company just quickly to ask if they knew any reason why I shouldn't use it. It says it lowers CCL and you can swim 20 minutes after adding it. They said it was fine. So I followed the instructions carefully and it just seemingly ate all FCL and CCL. Not the desired effect for a commercial pool where I needed to verify that FCL is still above 1 ppm.

I'm repeating the process 4 days later because CCL was again over 0.5ppm despit UV and Ozone being back on, and researching this chemical. So far I've found that it's and oxidant similar to Potassium Monopersulphate so it interferes with DPD tests and I am getting higher TCL and CCL. What I don't understand is why I am not getting a FCL reading on either my Palintests or on the computer out the back. Honestly I don't know how the computer out the back works ouside of water flows over it and it gives me a live FCL reading. It's called Waterlink. So what is this chemical doing? Is it bleaching the DPD 1 but not the DPD 3 somehow? Somewhere I read these chemicals can result in higher chlorine demand so how often if at all should I use it? and/or general thoughts?

So many questions and so much frustration. Sorry for the word vomit.
Thanks for reading this maniacally written story from an undertrianed, undervalued plantroom opperator, feeling the pressure.

Tonight I cleaned my filters and attempted to tighten the filter body clamp on my Clean and Clear Filter housing, but the t-bolt and/or nut is stripped and will not tighten. After many attempts, I drove to Lowe's to try and find a temporary replacement nut at Lowe's but to no avail (they were completely out of one that might fit the clamp's t-bolt). I have ordered an aftermarket clamp on amazon, but now my worry is what do I do to keep my chlorine from dipping too low until the part arrives sometime Sunday. I have a SWG that usually keeps my chlorine at good levels. In the meantime, what is the best way to circulate liquid chlorine in my pool until I turn my pump back on (hopefully Sunday)?