bulkheads + surface skimming tube...


New member
OK, I'm getting closer and closer to starting the 155/175 bowfront upgrade of my dreams. I don't really love the typical intank overflow boxes in most tanks, and have read alot about the desirability of "calfo" style surface skimming, but, I'm also concerned about cleaning and maintenance of said approach. So I've been thinking about something like this...

First, in the back high corner of each side of the tank I would put a 1 - 1.5" bulk head with strainer. I would then take a 5-6' long piece of 3-3.5" ABS (black) pipe that had slots cut into it along the length on one side, and cut it in half and create some type of coupling/slip fitting so that I could put it over the two opposing bulk heads, across the back of the tank, thereby covering, but not disturbing the bulkheads. Assuming I can get the thing on in the first place with my slip/coupling or fitting, that means I should also be able to take it off for cleaning/maintenance.

Since the bulkheads themselves are mounted high, I figure that having a watertight seal where the sleeve overflow skimmer meets the side of the tank is not really important.

Does this make any sense?
This is similar to what I'm doing in the 145g tank I'm setting up this week except I don't think that the overflow really needs to be so long.

If you think about it, a long overflow would have to be EXACTLY level to skim the top 1/16" of surface water along its entire length, and even if it does that, is this better than skimming the top 3/16" of water along a shorter length?

I've used something like this in a 90g that was less than a foot long and it skimmed everything off the surface just fine. I'm planning to use a "T" fitting from a bulkhead inside the tank and then attaching about a foot of 2" ABS pipe with the slots to each side of the "T". A cap goes on the outer ends of each piece of pipe. Cleaning will be easy.

I'm going to put the slots perpendicular to the length of the pipe so the rotation/height of a slot doesn't need to be overly precise. Lengthwise is probably fine too but installing the fittings with the slots perfectly level to the water surface will be relevant. When I'm happy with the function (after experimenting with the size and direction of the slots) I'll use some black PVC pipe (Savko) instead of the ABS.
Perpendicular slots are what I had in mind as well, sorry my explanation didn't make that clear. As far as running the whole length, that's just the conclusion I reached after reading about calfo overflows.

I also figured that with the totl-length design, that since the actual overflow "box" wouldn't be hard plumbed to the bulkheads, but just slipped over them, if it got hit by anything it would be that much less likely to crack the drilled hole.