If you smell anything other than bleach, like a perfume, don't use it. Period.

One thing people forget is that each summer is different. One summer may be relatively bug (as in biters) free, the next may be mosquito-central. There's different levels of pollen, and other contaminants. It depends on the amounts of rain in the spring and summer and the amount of sunlight.

Saying that, this summer seems to have been one where there was a lot more biological stuff getting in the pools. My usual vacation ritual of having someone dump 1 gal of bleach in the pool every other day failed, and I came home to a mild algae infestation--for the first time. My system always worked in the past. So why did it fail? I don't know, but I just think there was more stuff to metabolize.

I don't know if this is right or wrong but it seems to fit the facts.