JamesS wrote:
Can the sand be sucked up with the gravel vac?
if you just shove a gravel vac straight into the sand into the same way you would gravel than you are going to suck some sand up. You clean the sand in a different way you do gravel. Once you get a siphon going to hold the vac as close to the sand as you can without actually sucking any up, but still removing any bits of debris that will be sitting on top of the sand. You could also try pushing the vac at an angle rather than vertically, if you're careful you may find that the sand doesn't get sucked up.
It will take a little bit of practice but once you get the hang of it you'll find that you can clean the tank with sand a lot quicker than you can one that contains gravel