Lower lights = less hours per day. I'd cut by 30-40% (e.g., if you're at 10 hours a day go to 6 hours a day). Like Dkuhlmann said, vacuum it out when you do water changes.
What are you replacing water with? If you aren't filtering your tap water, consider a RODI unit or buying ready-made from a reputable LFS.
Is your circulation pump in a sump returning water to the DT? That's probably plenty unless you have a huge tank, but you want additional powerheads in the tank moving things around. I have a 65g with 4 additional powerheads on a wave maker.
Last...what kind of cleanup crew do you have? They eat up the leftovers to make sure the nasties don't have a lot to eat...in my 65g i have ~50 blue leg hermits, ~50 snails, a couple shrimp, and another ~40 porcelain crabs (these came as a free bonus with my live rock...side note: If you need live rock, go with Tampa Bay Saltwater. Fantastic. I have no affiliation with them but they are great).