Modified External Durso

The overflow's purpose is to keep the water level in the tank constant by moving excess water to the sump (or other filtration device). The most common overflow is a box going from the bottom off the tank to the top. Slits are cut into the top of the box. As the water level rises above the slits, the excess water flows to the other side. From there, the standpipe moves water out of the tank. The notches means that the water is being pulled off the surface of the water, having the benifit of better water turnover at the surface.

Since my main tank had been drilled in the back corners, a normal standpipe was not going to work. Having researched, I found some plans for a modified Durso standpipe The advantage of the Durso was the quiet sound over older style standpipes.

Hopefully this set up will combine the benefit of a normal overflow box skimming water off the top with the quietness of a Durso, all with a back-drilled tank instead of one drilled on the bottom. The other advantage is that it does not need to take up as much room in the tank for the overflow box that goes all the way to the bottom of the tank.

Trying to keep on a budget, I ended up making my own overflow boxes. I bought two plastic boxes (which happened to be almost the perfect size - I figured I would be searching for weeks for the size I need) and notched them myself. The plastic boxes were found at a local hobby store. I used an Xacto knife with a plastic saw attachment to cut the notches. I also had to buy a 1.5" carbon drill bit to drill the hole inthe back of the box.

The total cost for the two boxes plus the knife and drill bit was under $15. As the only overflow boxes I found online were going to cost me about $40 *each*, this was a source of a lot of savings.

To see what happens to the water after it enters the overflow, check out the plumbing page.

Last updated: 15 June 2003

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