Power Head Placement

[spartanph]

I have an 85 gallon tank with 2 Aqua Clear 70 power heads. LFS recommended that I place them in the rear corners hanging from the top pointed accross the tank like an X.
I have about 90 pounds of live rock and plan on a fish and reef tank. Is this enough water flow and should I change the placement or direction of the power heads?
Thanks

 

[jsgreer1]

how much flow do they produce? the recommended flow turn over rate ive seen on this site is 12x to 15x and as far as the position i dont know i have mine similar to that and everything seems to be going fine.

 

[ejensen]

Originally Posted by jsgreer1
how much flow do they produce? the recommended flow turn over rate ive seen on this site is 12x to 15x and as far as the position i dont know i have mine similar to that and everything seems to be going fine.

That is crazy to have that much current in a tank. 15x. With that much watermovement the fish are just going to get pushed around in there. manybe if you have a reef tank.

 

[ktsdad]

Originally Posted by ejensen
That is crazy to have that much current in a tank. 15x. With that much watermovement the fish are just going to get pushed around in there. manybe if you have a reef tank.

Sorry, but I have to disagree with you on this.
10-15 water turn over is normal for all tanks, more for reefs.
I have never seen any of my fish "get pushed around".
Water flow is not only for keeping water moving around filter feeders, it is also very helpful in keeping detrius and other unwanted debris suspended in the water column so it can get suck in by your mechanical filtration.
To answer the original question -
You want your powerheads to provide a good flow in and around your rocks (or whatever decorations) so you don't have any "dead" spots.
Usually a nice X patten is good.

 

[fuppets]

I have 20x in my 55 gal with 3 powerheads and my HOB filter. I have two aquaclear 50's pointed as the LFS told you and a zoo med power sweep about 1/3 down the back next to the filter sweeping away from the filter.
When I added the 50's I was worried about that being too much for the fish, but it looks like they love it. They are a lot more mobile and actually like swimming right in the flow.
The sand bed is slowly being blown away from the front glass right in the middle of the tank.

 

[spartanph]

I added a third powerhead today and repositioned the existing 2 and it made a huge difference. The oily film on the water surface is now gone and the protein skimmer seems to be collecting more.
The original 2 are still in an x but I lowered the one on the right side and directed it more towards the surface.
The new powerhead (also an aqua clear 70) I placed on the left side towards the bottom of the tank and angeled it towards the protein skimmer with the flow all behind the live rock at the back of the tank.
The CC bed moved around a little initially but everything seems to have settled now. My fish do seem to be more active now also.

 

[ejensen]

Do you have a fish tank or a powerhead tank? I hate the look of a tank full of equiptment. I like to keep everything under the tank and out of sight, except for the exhaust tubes and the built in overflow. Not even a heater to see. Your tank do what pleases you.

 

[spartanph]

The new powerhead is all hidden behind the live rock. I'm not setup with a sump yet so I don't have much choice on the heater and skimmer being in view. The other 2 powerheads are pretty much where I gather most people have them in the top corners. The one I lowered slightly on the right is more in view that it was before but not much.
ejensen do you have no powerheads in your DT?

 

[ejensen]

No. Not one. If you don't have a sump I could see why. I just use a mag 9.5 split into two exhaust hoses.