Before I took over the maintenance, my wife did things the pool store way. She used bags of powdered shock to chlorinate. Took the water in to test every few days. Added what they told her to. Everything would be fine for a while, then algae would bloom up, they would say double the bags of shock added, or even triple them. Do this for a few days, and the pool would clear up, and we would go back to a bag a day again. Eventually it would begin again. She swore that it was a conspiracy, and that the pool stores added something to the mix to cause the algae blooms, thus causing you to buy algaecide, clarifier etc.
Well when we moved, I was told that she was done with it, so I found poolforum.com and started using the bbb method. Ever since then I have always wondered, if the bags of shock contained stabilizer, and it would build to a point where it would no longer be sanitary and a bloom would develop, using more of the same would cure it, and we could return to the original dosage. My question is, did the stabilizer get consumed, or did it just appear that way?