Bottom intake on your overflow box?

[petedoc]

I am trying to decide whether or not to drill holes in my new tank overflow box. It is designed as a top overflow, but I am trying think ahead and plan to drill bottom intakes. The tank is planned as bare bottom, so sand coming into the intake wouldn't be a problem. Do any of you have experience, good our bad with this design option?

 

[ct_vol]

One downside of it is that in case of power outage, your water level will drop to the bottom of your overflow return, instead of the top of your overflow box... This can be a difference of an inch or even two... That can be quite a bit of volume depending upon the size of your tank... So you'd have to have that much volume available in your sump so you don't have a messy living room... HTH

 

[petedoc]

Fortunately this overflow box is actually not being used as a return to the sump. It is only being used as a closed loop for flow.

 

[petedoc]

The other overflow box is a traditional setup, but the tank would only drain anyway to the top of the standpipe returns.