Is 1 enough???

I have a 90 gallon mixed reef that seems to be leaning more and more toward SPS domination. I keep pulling out the softies to make more room for my acros. I seem to have quite a bit of brown algae that grows on my sand bed. Do you think a single MP40 is enough flow for this tank or would I be better off with a second, or do I need more flow.
If i do need more flow what powerhead would be recommended.

 

It might be OK but I think a single source of flow in a tank is not optimal. I think you'd be better off with 2 MP10's or MP20's. If you want to keep costs down you could get an MP20 or 40 for one side of the tank and put a Koralia or something on the other, it will be much better than flow from one powerhead IMO.

 

I agree. The MP40 will do an awesome job of getting chaotic flow to the whole tank, but they do tend to have some fall off towards the far end. To keep SPS on both ends of the tank it will help a lot to have some good brisk back pressure pushing against the MP40.

 

Agreed with the above. I use an MP40 on one side a a K1 to keep the other side moving. Although it really depends on your rock work. I have a sort of wall half way in my tank so the flow hits that hard, but doesn't really make it to the other end. If you have lower rock work then the 1 MP40 should be fine.

 

my rock work goes about half way up the tank. I just added a modded maxi jet to the tank to see if this helps. If I llike the outcome maybe I will pick up another mp40 for the other side of the tank. I just like the clean look of the vortech powerheads.

 

I have a 75 which is probably same L&W as your 90, but a few inches shorter. When I did my aquascaping, I only built the rock up in the back at the overflow. The rest of the tank, the rock is about 2/3 back from the front leaving space for water to flow all around the rock. This was primarily to give the fishes more swimming room, but it worked out nicely for my single MP40W which seems to circulate the water just fine. I have two returns from the sump which I direct to the corners of the tank and the middle. According to my sand, the MP40 is moving water nicely. I have sand drifts which I have to move back to the end of the tank opposite the MP40 every week. The only weak spot I can see in under the large cave/recess I have. But Mr. Goby takes care of that for me.

 

My rock work is fairley open with lots of caves for fish to swim and I have a return at both corners of my tank. I dont get any sand movement in my tank at all. I seem to get buildup at both ends of the tank and a bit in the center of my tank. Here is a recent pic of the tank to give an idea of the rock work.