You could try different placements and flow settings, this will largely be trial and error though. A wavebox would help. To a large extent though, this detritus will just need to be periodically siphoned off, I once tried a bare bottom 120 with a wavebox and a 6305 and for all that flow and the idea that the barebottom would be cleaner, it didn't pan out, between boring sponges and worms creating larger rock debris and a foxface with huge turds, nothing I did could eliminate the detritus piles near the rocks and weekly siphoning just became part of the maintenance and I set up a bucket with a filter bag and siphoned through the bag every 5-10 days and just dumped the water back. Basically, you may be able to improve things but I wouldn't expect a cure and the main thing I learned from my bare bottom experiment was, it is better to have mid grade size sand with detritivores to consume this stuff instead of trying to run a sterile tank, you eventually give up on the intensive labor and I have my doubts that the nitrates stay any lower for all the work.
