I've filled some empty bleach bottles with quikrete (dry - did not mix) to use to weigh down my steps. They work well, though I do notice that I can hear some air escaping when I take them out, so now am worried about the finer powder escaping into the pool. I do know that some bleach bottles allow for venting for off gassing.
Should I seal/glue the caps shut?
Pour a bit of water in there to turn the dry quikrete into concrete?
Add some bleach to kill anything that may live in there?