Sump questions

[TigerBarbs]

How do you determine the overflow box gph? How does it not overflow from power outage? How do you determine the return pump size? I'm thinking about a 15 gallon sump for my 29 gallon reef and have lots of questions.

 

[Terrance]

How do you determine the overflow box gph?
If i'm understanding your question correctly, then all overflow box tells you the max gph.

How does it not overflow from power outage?
There's actually a few ways. Do more research. The amount of resources & effort you put into try to prevent flooding with overflow boxes will outweigh the resources and effort you put into drilling the tank.

How do you determine the return pump size?
If you have a 29g, then try to get at least 290gph pump (10x volume). The height and 90 degree elbow pipes also decrease flow, so aim around 400gph. There is no general rule, but you have to think about the sump as a whole. What will you put into the sump?

 

[TigerBarbs]

I will be putting an algae turf scrubber in it.

 

[Terrance]

Oh ok. Flow wouldn't matter too much. Match the gph of the return pump with the overflow box. If your overflow box has a max of 500gph, then you would want to aim close to 500gph. Remember the elbows and height of the tank will decrease the flow, so aim for a pump that will be a little stronger. This calculator might help: http://reefcentral.com/calc/hlc2.php

Usually, the pump will tell you the flow with certain heights. Here is an example: Danner Supreme Mag-Drive Aquarium Water Pump/Powerhead

HTH