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[Surfer]

Sorry for all the questions guys but I want to know what to do to get my tank right. I'm going saltwater with my 45 gallon. I'm gonna put two penguin bio wheels on it. I read it does need live rock. Ok thats unimportant. My question is:
What exactly does a powerhead do and do I "have" to have one.

 

[OrionGirl]

Bio-wheels are not good for SW--they increase suraface agitation, which increases evaporation and salt creep.

Powerheads are small internal pumps used to create water movement, and reduce areas with little or no flow.

 

[joephys]

power heads can also run under gravel filters. You might get more info on live rock if you as in the salt water forum.