I would go with about one inch per four gallons in a reef set up. Your main concern is not so much waste management but oxygen availability. There are things you can do to slightly skew things in your favor, such as running air stones in the sump, a good protein skimmer, keep the water surface of the DT moving well and the SG on the low side.
_________
90g HW: 20g Sump/Fuge, ETSS PSw/Mag9.5, CPR OF/Rio 2100 RTN, 3K3 1K4 PH's(4200GPH ttl flow), 300W htr, Gnd Prb, Denitrator, Tek 8x54W T5. Fish: Hippo Tang, Hmbg, Y-T, Ylw dmsls, Coral Beauty, 8 Line Wrasse. Inverts: HC, CBS, P-mnt shrmp x2, Sandstar, Sea Apple. CUC: 130 D. Crth/35 F. Crth/30 Lg Nrts/25 Vibex/4 Turbos Corals: Frgspwn x2, Kenya Tree, Doughnut Coral, GSP, Zoas x2, Shroom rocks x2, Lobo Brain, Turbinaria, Mshrm Lthr, Fngr Lthr Other: 145# LR, 1-2" LS DOB 5/7/08
[SIGPIC][/SIGPIC] | 
