I had a powerhead pushing 150gph but upon your suggestion I just bumped it up to 500gph model haha The flow has already seemed to make a difference. Obviously on the sand but even the rock has stopped progressing in darkness. Not to mention, the fish absolutely love it ha! And as far as a sump, I do not have one. Just a HOB, 12lbs of Live Rock, 10lbs of LS, 50W heater and now 500gph pump. I do 5g water changes biweekly on my 29g and I figure to do a gallon a week on this tank.