TL: I'm sure you're getting sick of answering my lame questions about MP40's, but I have one more for you.... when you just have your return pump running, how close is your water to your cross braces? Mine literally licks the cross brace, with my mag 18 return pump dialed down. I'm going to swap out my 18 for my spare 12 when I get the replacement parts ( will come when the VorTechs do). I'm hoping I can get away with running the 12 on 100%... Once the MP40's go in I plan on directing my return water behind the rockwork.
I've been trying to reply to this since late last night, but it doesnt seem to go through, let's try again...
Without the MP40s or MP10 on, my water is about 1.5-2" from the braces. I run a return pump rated at 1200gph, split to two returns in the tank (one at each overflow). One return is far stronger than the other. I have that one running across the back/middle of the tank from one side to the other and the weaker return pushes towards the front glass.
The MP's all run at about 85% in Nutrient Transport Mode. Before I had the 10, the two 40's ran in Random - Reef Crest mode at about 80-85%.