I completely agree. Which is why I have different types of media in both of my ehiems. I also did notics the flow is not as great as I would like it. I have a sizable pump that I believe was designed for ponds. Im thinking about rigging it to one or both of the canisters to relieve the stress on the canister motors while increasing my flow. My power heads seem pretty worthless for anything other than moving the water and taking up space. The reverse flow option is not powerful enough for true undergravel filtration either IMO.
But I bet it would work wonders on a smaller aquarium to have a reverse flow power head/undergravel filtration and an aquaclear. I have used aquaclear before and I like them.