External Overflow Strainer

I have a few tanks that are drilled toward the bottom and use a 1/2" PVC standpipe to set the water level.

I started off with a cap style, but if it became clogged, I'd have a spill. So I came up with these, that still provide straining, but if the water gets high enough it will still drain unimpeded.

This style goes ouside of a a male 1/2" PVC fitting.