powerhead cycling?

[momac]

I have two powerheads (maxijet 900s) on an AP24. Is it common to cycle a powerhead (or both) off during lights out ?
Thanks gang!
:)

[afelder]

It's a matter of preferene. Depending on what you're keeping they may prefer higher flow. SPS tend to prefer higher flow. Others will be fine with one at night as long as you have decent surface agitation.

[Agu]

Most of the controllers and wavemakers have a "night" mode with lower flow, but typically they're used on larger tanks.

Eric Bornemann wrote an article in RK magazine that indicates the drop in o2 levels at night is significant. I've also seen several posts on RC where seemingly healthy tanks suddenly have dying fish overnight, oxygen depletion is a leading suspect in those situations.


The need to Breathe ........... (http://reefkeeping.com/issues/2005-06/eb/index.php) is part one....

With smaller covered tanks I'd be hesitant to reduce the flow at night.

[momac]

Thank you both for the insight.