I find it odd that it's sucking up the sand to begin with, honestly. They must be digging a lot? I don't use that brand of HOB but mine are similar and don't get any sand caught. Is the in-take tube one long tube or two combined? If it's two combined, just remove one to make it shorter (I know AquaClears and Whispers often have two tubes, not sure about TopFin).
A canister filter could be positioned so that the in-take is far from the sand and it should be gentle enough to not stir it up.
A canister filter could be positioned so that the in-take is far from the sand and it should be gentle enough to not stir it up.
