power head question

[2revup]

how many power heads should i have in a 4ft tank.
the reason i ask is i am finding it hard to get a flow toward the bottom of the tank, and it looks like I am getting a cyno out break, so i need some flow down to the bottom, i currently have
2 x 3600L/ph and a 1200Lph the 2 large ones are at the top one each side to agitage the surface water.
one points right toward the middle and the other left like \ /
the 1200 is near the bottom but that seems to be doing very little to get rid of the cyno.

is there a better way i should be pointing the power heads?

 

[afishyonados]

Have you considered adding an external pump strictly for circulation? There would be less heat transfer than adding more powerheads.

 

[melosu58]

How often are you feeding? Are you testing and what are the results? Are you doing PWC`s to get rid of excess nutrients? Just some suggestions

 

[angelscrx]

Glass tank or acrylic? The external pump is a good idea. Power heads can fail and put heat heat in the tank. Several different options. You can place PH down lower in the tank or aim the ones higher up down towards the sand.