Do I need two Powerhead

[dschriner]

I have a 24gallon cube do I need a powerhead this is a coral tank

 

[Spare time]

Yes. All coral tanks, and in reality, all tanks, should have one or two (ideally at least 2)

 

[Billdogg]

Although my tank is larger (120DT/40sump) I use 4 powerheads and a pair of Gyre 250's to get the random flow needed to prevent dead spots where detritus can accumulate. IMHO, one power head is never enough. 2 or more will give you much better results. You should be aiming for somewhere around 30x turnover in a LPS or soft coral tank, and at least double that for SPS. My tank averages 70+x turnover and briefly peaks about 100x.

 

[Uncle99]

I have a 24gallon cube do I need a powerhead this is a coral tank

A pair in that size would be better.