180 Gallon Powerhead Placement Adive?

Hey All,
I have just recently setup a 180 Gallon Aquarium. I did this to combine my 75 gallon and 90 gallon tank into just one main big tank. I am finding that I am haveing a heck of a time getting my flow right in such a large tank with all the equipment that I had in the two other smaller tanks.

Here is a picture of what my tank looks like rock scape wise from the front.



For my return I have a Mag 18 pump that is ran with 3/4 inch PVC with two 90 deg elbows to a "T" that I have two 1/2 inch PVC to one 90 deg elbow on each side. They are pointed almost straight to the front of the glass as you can see in the picture. I dont think this is producing as much flow as I expected and I belive it is because I have the 90 degree elbows, a 3/4 inch ball valve (its fully open), and a 3/4 inch check valve.

On the right side I have one Hydor Koralia Evolution 1050 powerhead at the top front of the tank and one Hydor Koralia 4 at the bottom front of the tank.

In the middle I have a Hydor Koralia Evolution 1050 powerhead that is at the top back of the tank pointed to the front.

AND

On the left side I have one Hydor Koralia 4 at the top back pointed a little down towards the middle front of the tank.

As you can see I have cyno and I think its because of a lack of flow but not 100% sure.

Just a little detail on my rock scape. It dosent look like it but in the middle there is a slight opening/gap in-between the two piles of rock on the right and left.

Also all the rock is 3-4 inches from the back of the glass and I have little/no flow there.

Just looking for suggestions for some placement and what power heads I should add.

If money was not an issue I would have two mp40s on both sides of the tank but I am not able to spend that much money.

So I was thinking of adding two Hydor Koralia Magnum 7 power heads to the tank and really have not thought about position.

Thanks for any help and suggestions!
Cole

 

I would recommend bringing one more of the PH's down so it flows across the sand bed on the left side. You should be able to find a happy location where you get flow in the bottom half, but it won't push the sand around. It should be pointed parallel to the sand, not toward it.