Risky: another "don't try this at home?"

[HKfshkpr1]

I am not very good at plumbing but I "dreamed up" this "simple" set-up one day. After that I just had to try it without any further research. So someone else may have done it.

The reasons for a "bulkhead at a lower tank level" are: (1) I can filter more "particulate" matters.(2) Easy to hide with a rock, etc.

I used 1 inch 200psi PVC( thin wall) pipes and I est. the flow rate is about 350 GPH. The bulkhead is about 4 inch from the bottom. The water level is about 1.25 inch from full (right at the "T" fitting). The key to make this work is the "vent" at the top of the verticle pipe( covered with a white coarse filter media).

You can adjust the "angle" of the horizontal pipe to adjust the water level. See the "horizontal" pipe is "lower" at right side? If I raise it to a more horizantal position the water level will rise but "must keep" the "T" as the "highest point" to ensure "vent operation".

Note: to ensure "no flooding", especially in a tank with lots of flowing debris( dead plants, seaweeds, etc.), a smaller bulkhead can be installed right at the top to drain the overflow. I don't have one and I clean my bulkhead screen twice a month and have had "no issues" for 7 months. Must observe water level change "everyday" to determine when to clean it.

This tank backview does not look clean at all as I am trying to manipulate the sunlight going into the tank.

 

[BoomCorals]

I’m not sure I understand, but wouldn’t this cause a sump overflow if your return pump went down or lost power?

 

[HKfshkpr1]

I’m not sure I understand, but wouldn’t this cause a sump overflow if your return pump went down or lost power?

Good question. That's what the "vent" is all about. I forgot to mention that in case the sump pump is off, the water level in this tank will drop about an inch and a half max. The vent at the top of the vertical pipe will stop the siphoning effect( water level in this tank will "not" go lower than where the "T" fitting is).

But water returning to sump will happen even if you install the bulkhead at top as an overflow. The amount of water returning to sump when sump pump goes off depends on the flow rate of the sump pump, and the diameter of the return pipe/hose.

 

[BoomCorals]

Good question. That's what the "vent" is all about. I forgot to mention that in case the sump pump is off, the water level in this tank will drop about an inch and a half max. The vent at the top of the vertical pipe will stop the siphoning effect( water level in this tank will "not" go lower than where the "T" fitting is).

But water returning to sump will happen even if you install the bulkhead at top as an overflow. The amount of water returning to sump when sump pump goes off depends on the flow rate of the sump pump, and the diameter of the return pipe/hose.

Ah good thinking!

 

[ca1ore]

The 'problem' with this approach is that the biggest benefit of a weir-based overflow is surface skimming; which this doesn't do. Maybe not as much of an issue in the FW tank, but important for a reef. I get the desire to hide the bulkhead, but assuming an adequately circulated tank, there is likely no particulate removal benefit. Though, again, maybe different FW vs. SW.

 

[HKfshkpr1]

The 'problem' with this approach is that the biggest benefit of a weir-based overflow is surface skimming; which this doesn't do. Maybe not as much of an issue in the FW tank, but important for a reef. I get the desire to hide the bulkhead, but assuming an adequately circulated tank, there is likely no particulate removal benefit. Though, again, maybe different FW vs. SW.

You are right! I have fish only and did this mainly to try it out. I do have 3 surface bulkheads in the "main" show tank( from where this side tank receives water). When I have time I'll prob add one on the surface. And If I have to start from scratch I'll have both level bulkheads in all the tanks.