I have always put my canister intakes very deep, most cannot go deep enough, but I do as deep as they will go. Is this the best situation? What do you guys use? Or do you use surface deep?
Plus if things go south there will still be about 3 inches of water left in there too keep the inhabitants wet and alive.
It will never pick up all the debris, ever. The goal of filters is to create enough current to keep the waste suspended in the water column providing more time for the filter to collect it.