Plumbing my first overflow?

This is what I meant by strainer and also a pic of my overflow box, with a lid on no critters can get in and if they did they couldnt clog up a 1" pipe thats always open. That being said a lot of reefers dont run lids. You could make a strainer with a pvc cap and holes drilled in it as well.

The holes mid level in that picture are very deciving. There is a "inner wall" behind the slots which creates a 1/2inch space, the height of the "inner wall" is just below the top of the overflow so the water is pulled in from the lower rows of slots/holes then travels up to the top near the water level then spills into the overflow. The design is just so its pulling water from lower spots in the tank and not just the top. If the pump stops its not like its going to drain to those lover slots level as the "inner wall" prevents that. The main tank water will not drain below the very top slots in the overflow and the overflow with drain to the hieght of your main syphon drain. (Be sure to drill anti-siphon holes at the water level where your return pipe enters back into the tank though to prevent back siphon when the pump is stopped). You can see the "inner wall" in the below pic. The pic/ graphic that ClownFishAddict posted in the 3rd post of this thread also shows how it works and the "inner" wall.

Edited by Bryce - January 18 2013 at 10:34am