Perfectly Clear Pool Water. Chlorine Disappears Fast.
by Jason Hicks
I recently opened my pool up for the summer. Apart from a few leaves that found their way under the tarp the water was perfect. I vacuumed out leaved and topped off up my pool 30ft round about 24k gals, with about 1 ft of water. I checked levels, and all was on par minus the Chlorine. Water was perfectly clear didn't think shocking was required. Levels were as follows.
PH 7.2 FC 0 TC 0 TH 250 AK 90 CYA 50 TDS 600 PHOS 100
No Nitrates, no copper.
My Cyanuric acid was at 100 at the close of the season last year so I knew I didn't want to continue with my Trichlor that I had been using, so I ordered Lithium hypochlorite (hard water, high cya) but it hadn't arrived yet, so I used 2 gal of liquid sodium hypochlorite over the course of 3 days to try and get my chlorine up to no avail. Then yesterday eve I put in 3lbs of TriChlor as a last ditch effort to try and get my Chlorine up to no avail. I had my water tested again today after shocking last night and reading were the same apart from PH 7.4 and cyanuric acid is now 80... Am I just barely keeping my water sparkling and simply just need to shock one more time?
Hi Jason. First is you never need lithium hypo. It's too expensive, way overrated, and not any more effective than liquid chlorine. Next is you should never use granular trichlor unless your CYA is low. Your CYA was at 50ppm and now it's 80ppm. The range is 30 - 50ppm. As your CYA increases the FC level must increase as well. This is part of the FC/CYA relationship that needs to be met. For the FC to start to be effective you're going to need to run the FC at 8 - 9ppm. I would think this is one cause of the FC not being able to hold. One gallon of chlorine will treat 10k gallons of water. To give your pool a good shock, for 24k gallons, you'll need 3 gallons all at once. I would suggest, before adding any more chemicals to the pool, you do a 1/2 drain and refill to get the CYA down to an acceptable level, then shock the pool with 3 gallons.
Also, having a good test kit is important. Taylor K-2006 is what you need. I've made several detailed videos on how to use it. This seems to be a fairly simple fix.
Remember I also have eBooks and consults available if you require more detailed info.