Reefs.org Forums

[Matt_]

I am resisting your suggestion about the external overflow box because I do not want to (ok, I'm afraid to) drill multiple holes or an elongate slot along the back of the tank, which is what I would need to do to get decent surface skimming.

Are you having these holes drilled professionally?

One or two slots 1" deep will be much more structurally sound than even a single bulkhead hole. It's really not very hard at all, it took me about 30-40 minutes with a dremel.

I plan to drill the hole myself. I have a cheapy 1.75" diamond hole saw on order. I am uneasy about using the dremel tecnique, and don't have the tools.

In any event, I am having a difficult time understanding how an elongated rectangular opening can be more sound than a round hole. Corners lead to stress points and fractures. But I could be wrong.

It doesn't need to be rectangular. You can round off the corners the same radius you would on the circles. Imagine if you just shaved off the top 1/2" of one of your panes of glass. That's much more structurally sound than putting a hole closer to the center of the pane.

In any case, my tank has been through a couple 4.5 SF earthquakes with no problems. Those earthquakes did cause some leaks in some old fiberglass tanks we have.

[Uncle Mike]

Think I understand, the loop from the top of the tee isn't so much a Durso but a way to handle the excess flow from the leg with the gate valve if you have problems. Somewhat combining a single horizontal overflow with a Herbie method though relying on a single bulkhead, neat.

Waiting for the pictures.

Close. The loop from the top of the tee is a Durso. As I understand it, the Herbie provides the top loop as a back-up - just as you described. But water only flows through the top loop is the primary gets back-up.

My Durso loop also provides a back-up, but nevertheless also carries a small amount of the total flow. This rasies the water level in the external plumbing system so as to cover the bulkhead through tank, thereby eliminating the possibility that air will gurgle through the bulkhead.

[Uncle Mike]

I am resisting your suggestion about the external overflow box because I do not want to (ok, I'm afraid to) drill multiple holes or an elongate slot along the back of the tank, which is what I would need to do to get decent surface skimming.

Are you having these holes drilled professionally?

One or two slots 1" deep will be much more structurally sound than even a single bulkhead hole. It's really not very hard at all, it took me about 30-40 minutes with a dremel.

I plan to drill the hole myself. I have a cheapy 1.75" diamond hole saw on order. I am uneasy about using the dremel tecnique, and don't have the tools.

In any event, I am having a difficult time understanding how an elongated rectangular opening can be more sound than a round hole. Corners lead to stress points and fractures. But I could be wrong.

It doesn't need to be rectangular. You can round off the corners the same radius you would on the circles. Imagine if you just shaved off the top 1/2" of one of your panes of glass. That's much more structurally sound than putting a hole closer to the center of the pane.

In any case, my tank has been through a couple 4.5 SF earthquakes with no problems. Those earthquakes did cause some leaks in some old fiberglass tanks we have.

I see your point. I will have to think about it some more. Thanks.