5 days of "burn out"???

[chem geek]

Bioguard "Burn Out 35" is 29% Lithium Hypochlorite by weight while "Burn Out Extreme" is 47% Calcium Hypochlorite (so, Cal-Hypo). If your PB is having you use the latter (and 1 pound bags sounds like the latter), then this is a way of getting both chlorine and calcium into your pool, but normally you would add large amounts of calcium with Calcium Chloride. I don't know why the PB is having you add so much chlorine.

1 pound in your 12,000 gallon pool will add about 5 ppm FC so I'm not sure why your FC is already > 15 ppm (it also adds 3.4 ppm of CH). By the way, the Taylor FAS-DPD tester has 1 drop = 0.2 ppm when using the 25 ml sample while 1 drop = 0.5 ppm when using the 10 ml sample. Are you using the 25 ml sample? If so, then 5 ppm FC would be 25 drops and would explain what you are seeing. When you expect the chlorine level to be high, you can use the 10 ml sample in which case 5 ppm FC would be 10 drops.

My guess is that the PB is expecting there to be a lot of initial chlorine demand, but if you added 5 bags (5 pounds) you would end up adding 24 ppm FC. I doubt that the sun this time of year is burning off your chlorine that fast or that you have that much chlorine demand. Perhaps you would lose 1/4th of your FC level each day due to sunlight -- during the peak of summer it would be closer to 1/2.

Richard