Just an FYI. I know the regulars here probably already knew this but I've been maintaining my pool the "pool store" way for decades. Last year stumbled across this site while looking for an accurate calculator to speed my spending of pool store products. Now I'm a convert and I thank all of you for your valuable info.
I was told over and over to keep the stabilizer up. The closer to 100 the better. I added powdered CYA to supplement the tablets and shock powder of the day. The store loved the results as I was at 100 CYA and had a FC of 5. "That will clear up your swamp".
Soooo since the store is basically next door I would run over there for testing even after I learned the BBB method.
*** In a one week stretch they measured the CYA @ 99 and then 40. A different store that is more of a boutique pool store was going to be the tie breaker. They measured the CYA @ 142.
Today I am ordering the TF100 and kicking myself for not doing so earlier.
The pool is an oasis though. The key is a great big DE filter and an Intelliflo pump that can crank the water. Within 24 hrs. it was sparkling. I wonder how much less then the 11 gallons of bleach I really needed to use?? At least I won't have to guess on the maintenance levels.