[cole004]

I've just completed my second overflow. They are great and cost about $30.00 to build. I use 1"/25mm sch-40 PVC from Rona and get them to cut it for me. I've made the following Mods;
Attachment 1910

Mod 1
I place a "T" on the intake (B) and two that added two threaded ends and two stariners. The "T" helps skim the surface and reduces noise. and the strainer keep the fish in the tank. before I did this I did have a snail go for a ride to the sump.
Attachment 1913

Mod 2
I removed the air valve and prime it by sucking on Tube "C" Air really isn't an issue with this design
Attachment 1915

Mod 3
I place an end cap on tube"B" with a hole drilled in it to reduce noise. * Note that the end cap in not glued as you will need to prime the overflow using this tube.
Attachment 1914

A couple of tips:
In the mod 2 picture you can see a couple of felt pen lines on the top. I dry fit the overflow and place it in the tank, adjust the angles and then mark the lines so I can glue it perfectly.
You can test the unit in the bath tub using a 5 gal pale.
I found sanding the PVC in the best way to remove the printing on the side.
Don't over-think this, it is dumby simple to build, dry fit the peices together and test it in the tub then place it the tank and mark it, glue it and plumb it to the sump. It is very easy. i guess that it moves around 320 - 340gph. good luck and let us know how you make out.

Cole004