Tanks are all down right now, as the big move approaches (nothing sucks more than moving...aaarrrgghhh)...but, the tanks are/were:
55 gallon, 50+lbs of fiji rock, almost 700 gph in flow (this one was set up for three years without incident, and will be the bimac tank at the new house)...20 gallon sump, Rio pumps, 1" of sand on the bottom.
2 50 gallons, 50 lbs + of mixed rock, 400/350 gph flow, no sump (mixed fish tanks), 2" of sand on bottom.
37 high tank, 40 lbs of fiji rock, 200 gph, 10 gallon sump, 1/2" of sand...this will hopefully be the little cuttle tank in the new place.
We are going to adding on a 125 gallon tank too, but it is a plant tank for Piglet (my bichir)
I use a rainbow lifeguard portable system for the bottom vaccing weekly...has worked out really well for me !!