I have just worked out the plan for the manifold and decided to go with three inlet sponges and to help keep flow maximised go with 4 pipes returning to the powerheads, this is were I run into a slight snag.
Do I go with option 1 and place the powerheads at points A+B, A+C or B+C

Or do I go with option 2 and slightly re-jig the pipeing in order to have the power heads more central but evenly spaced apart

Another thing I was wondering is if there is a best flow direction, is it best to have one powerhead pushing flow down the back of the tank and one pushing flow down the front or is it better to have both angled towards the front of the tank to create a better circulation of flow ?

