I have a 10,000-13,000 Gal pool. I bought Bravo/HEB brand concentrated bleach from HEB in Pflugerville, TX. The bottle says its concentration is 8.25%. It is hard to interpret but I think it says it was manufactured Feb of 2014. It is now Aug 2014. I have numerous test kits: one is a Leslie's brand complete pro-care DPD test kit. I am sure it is a re-branded Taylor kit, but sure what the exact equivalent is.
My issue: I add a gallons of chlorine and the level gets to around 1 ppm free chlorine and it is barely at the bottom of the scale for the Leslie test kit. I also have another kit that came with the house that uses 5 drops of reagent to turn the water yellow. That test seems more sensitive at the lower end of the scale. It also confirms the level is around 1 ppm. I can't really measure total chlorine because added the 3rd reagent, the color is so close to the free chlorine level (near bottom of scale) that I have no confidence. It does get a little pinker/redder, but not by much.
It really appears to me that the chlorine is nowhere near 8.25% as listed on the bottle. I added 4 gallons on Wednesday, 5 more on Thursday, and 3 more today and cannot get the ppm of FC to 2 or more.
NOTE: The pool is crystal clear, the water looks great and there is no cloudiness or algae.
I did measure PH and it was originally high at 8.0. I added muriatic acid and it lowered to 7.6. The PH seems stable. The total alkalinity is 70 ppm. I have a gunite pool and the water in this area is hard with lots of calcium. I have 500-550 ppm for calcium and, again, no cloudiness. The CYA is around 80-90 ppm.
Do you agree that the bleach seems unusually weak? Has anyone else heard of bleach being so weak when it is "brand new" (used within days of purchase)?