This will be in the middle of my sump, with the filter sock and skimmer on one side and the heater and pump on the other side. I have baffles separating everything, but I'm thinking if I have the sand and rock in a container that fits the middle section, that would help contain the sand. The water would be flowing over the top of the container, little chance for sand getting into equipment, at least I hope so. I'm trying to get more diversity in the water in the form of copepods, etc. Almost two years old, and I don't see a lot of that going on, at least in my eyes. Wanted to give them a safe breeding ground. and eventually, my fish will really appreciate it.