90 gallon tank.. egg crate base(3/8") - Substrate a mix of PFS and Sahara sand "top coat" - (DW likes its appearance ) - Texas Holey Rock and lace rock up to half height. Eheim Pro 3 cannister - So far that's what the DW and I are planning...Eheim has dual intakes, I assume one each end. I am interested to know your thoughts about adding one or two power heads and an UGJ system to keep the detritus off the sand and from collecting around the THR and lace rock. Is there an issue with sand substrate blowing around and clogging up? Too much flow for a 90 gallon? Do I need to adjust cannister filter intakes height? All comments greatly appreciated and thanks in advance!