i wanted to give my critters places to hide while trying to provide lots of flow, then later on, I had multi tiers to mount coral and softies depending on light requirements, the high light demanding ones I could put near the top where i had the 'flat pieces' and the lesser ones towards the middle and bottom. I put in two Koralias model 4 and wow what a difference, lots of flow, maybe too much flow as my fish and shrimp are now hiding in the rocks more, I had three but the third was just too much. Thank you for all the helpful suggestions, no I did not take any offense at all Squeak... its good stuff!
Now I gotta make a sojourn to the homedepot and replace my water heater, the bottom is all rusted out! Looks like i havent been draining the thing like I should have...