My new (?) boxless overflow design

[Anonymous]

After reviewing countless threads about internal and external overflow box designs, I have come up with following design. The design is a combination of various known designs and eliminates the need for either an external or internal overflow box. I do not know if this has been tried before, but I would like such critiques.

I know a drawing would help, but I will do my best to describe the confuiguration.

Inside the tank:

A single horizontal pvc pipe is positioned along the top of the back of tank at the water line. The pvc pipe contains numeroos holes, slots or a groove along the top of the pipe into which water will drain.

One end of the pipe is connected to a bulkhead fitting through the back wall of the tank about 3" below the waterline.

In short, the horizontral pvc pipe replaces a traditional internal overflow box while still drawing water from the surface of the tank. The pipe will not be very noticeable if painted black to match the back.

Outside the tank:

A pvc "T"-fiting is connected to the bulkhead in a vertical oreintation (i.e, the middle leg is connected to the bulkhead).

The downward pointing leg of the "T" runs to the sump and includes a gate vale to limit water flow therethrough. This leg is the main drain line and is intended to carry 80-90% of the total flow to the sump.

The upward pointing leg of the "T" connects to a 90 degree elbow, and then to another vertically oreinted "T". The top of the second "T" has a cap with a event hole. The bottom of the "T" runs to the sump (or a refugium). The bottom of the horizontal leg of the "T" (connected to the elbow) is positioned slightly above the top of the bulkhead fitting. This leg is a typical Durso design and is intended to carry only 10-20% of the total flow to the sump, as controlled by the gate valve on the main drain leg.

Summary:

The system is adjusted by closing the gate valve on the main drain leg until at least some water is forced up and over the Durso "T" and down the secondary drain leg.

The Durso leg is designed to maintain the bulkhead under water so that air will not be sucked from the horizontal pipe in the tank. The Durso leg also serves as a back-up in the event that the main drain leg gets plugged up.

My hope is that this design will provide a very low profile within the tank by eliminating the internal overflow box. It also eliminates a bulky box on the back of the tank, and simiplifies the number of holes needing to be drilled through the back of the tank. It should be virtually noisless. I plan to use this design on my 37g tank, using 1" pvc throughout. I figure this design will handle at least ~300 gph. Higher flows can be achieved with larger pipe (obviously).

So what do you all think??

 

[Anonymous]

Sounds like yours is bacially a horizontal through the glass bulkhead with durso design.

I did an inverted s trap. Which is an over the back design.

Then modified it to allow better "hanging" on the tank.

Another modification is to run the intank tube up the surface then down for an in tank durso effect. That way the in tank part determines tank water level.

 

[Anonymous]

I'm confused about the pipe inside the tank. You say it is horizontal, at the top of the tank, but that it is connected to a bulkhead 3" below the waterline. Can you describe it in greater detail?

 

[Anonymous]

I'm confused about the pipe inside the tank. You say it is horizontal, at the top of the tank, but that it is connected to a bulkhead 3" below the waterline. Can you describe it in greater detail?

The way I understood what he described was basically he drilled a hole in the back glass up high. To the water reached that level then started overflowing.

Then you use a bulkhead and plumbing to tweak the water level and move the water to the sump.

least that's what I thought.

.02

 

[Anonymous]

I'm confused about the pipe inside the tank. You say it is horizontal, at the top of the tank, but that it is connected to a bulkhead 3" below the waterline. Can you describe it in greater detail?

Sure. First, think of a typical internal overflow box. Tank water flows over the top edge of the box, into the interior of the box, and out through one or more bulkheads extending through the back or bottom of the tank.

The idea is to replace the box with length of horizontal pipe. The pipe is positioned at the tank water line. One end (or both ends) of the pipe are connected to the bulkhead fitting via a pair of elbows (or a 45 and an elbow). The pipe has openings along the upper side (holes or slots). Tank water flows through these openings and into the pipe, and subsequently through the bulkhead fitting.

The problem with a typical internal overflox is that it must be big enough to cover the bulkhead fitting. This is not necessary if using a slotted pipe directly connected to the bulkhead fitting.

I saw the slotted pipe concept at RC ( ), but they all complained that it was not silent since the bulkhead was not fully under water. I spent the weekend thinking about to resolve that issue.

 

[Anonymous]

To run quiet you need to have the water enter the pipe underwater. Like a elbow pointing down with an air bleed hole on top. The horizontal slotted pipe will be noisy because it is sucking water at the water air surface. Which allows the rushing water noise to escape the the room vrs being traped in the pipe and muffled.

my .02

 

[Anonymous]

I'm confused about the pipe inside the tank. You say it is horizontal, at the top of the tank, but that it is connected to a bulkhead 3" below the waterline. Can you describe it in greater detail?

The way I understood what he described was basically he drilled a hole in the back glass up high. To the water reached that level then started overflowing.

Then you use a bulkhead and plumbing to tweak the water level and move the water to the sump.

least that's what I thought.

.02

Yes and no.

The horizontal pipe is at the tank waterline. The bulkhead is below the tank waterline, probably 3-4" below the water line. The end of the horizontal pipe is connected to the bulkhead by a pair of elbows, with perhaps a short vertical piece connected therebetween.

The outside Durso is positioned so that it maintains the water above the bulkhead to prevent gurgling.

Maybe it will help to describe the locations of some of these components on a vertical scale relative to teh tank water line:

*tank water line = 0

*horizontail pipe, as measured along the bottom of the slots or row of holes = -0.25" (assumes a weir height of 0.25")

*bottom of external Durso bend = -2.5"

*top of bulkhead fitting = -3"

In this example, the water inside the pair of elbows connecting the horizontal pipe with the bulkhead will have a water level of -2.5", as dictated by the height of teh external Durso.

 

[Anonymous]

To run quiet you need to have the water enter the pipe underwater. Like a elbow pointing down with an air bleed hole on top. The horizontal slotted pipe will be noisy because it is sucking water at the water air surface. Which allows the rushing water noise to escape the the room vrs being traped in the pipe and muffled.

my .02

I think I covered this above. The slotted horizontal pipe is intended to function like a typical internal overflow box.

In any event, I could replace the elbow at the end of the horizontal pipe with a T having a cap with a vent hole above the water line to allow any air drawn into the pipe by the water to escape.

 

[Anonymous]

sounds like a well thought out solution.

 

[Anonymous]

If you want my honest opinion, I think it will look clunky and awkward inside the tank. If it has an elbow that means it will be sticking at least 2" into the tank.

Have you considered two external overflow boxes? Then you could put the Vortech between them at the top.

 

[ReneX]

I saw something similar on another site...after reading about this, I was wracking my brain trying to remember where I saw it.

http://www.nano-reef.com/forums/index.p ... low&st=120

I don't know how it is on aesthetics but the tank owner says it's pretty quiet.

 

[Anonymous]

if i were you i'd go with a simple external durso and a small overflow box at the top of the tank.

Lemme see if i can find a pic.

But instead of the external box, put the bulkhead through the tank, and build a small overflow box to cover the elbow. if you're using 1" the overflow box will be about 3x3x3" If you put a small piece of pipe between the bulkhead and the Tee, then you can fit the vortech motor between the pipe and the tank.

Which means the only place you can't fit the vortech is where the small overflwo box is.

B

 

[Anonymous]

If you want my honest opinion, I think it will look clunky and awkward inside the tank. If it has an elbow that means it will be sticking at least 2" into the tank.

Have you considered two external overflow boxes? Then you could put the Vortech between them at the top.

Maybe. I just ordered the hole saw and pair of bulkhead and low profile elbow fittings from glass-holes.com. I plan to dry assemled all of the plumbing, and perhaps test it on a rubbermaid tub, before making a fianl decision. If the arrangement does not perform as expected, or if the interanl pipe looks "clunky", then I will go with a low profile interanl oveflow box. But I doubt that a 1" horizontal pipe, painted black, and at the water line will be very noticeable.

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.

 

[Anonymous]

I saw something similar on another site...after reading about this, I was wracking my brain trying to remember where I saw it.

http://www.nano-reef.com/forums/index.p ... low&st=120

I don't know how it is on aesthetics but the tank owner says it's pretty quiet.

Yes, some of these photos is what inspired me to dig into the slotted horizontal pipe idea.

 

[Anonymous]

if i were you i'd go with a simple external durso and a small overflow box at the top of the tank.

Lemme see if i can find a pic.

But instead of the external box, put the bulkhead through the tank, and build a small overflow box to cover the elbow. if you're using 1" the overflow box will be about 3x3x3" If you put a small piece of pipe between the bulkhead and the Tee, then you can fit the vortech motor between the pipe and the tank.

Which means the only place you can't fit the vortech is where the small overflwo box is.

B

That is more or less where I started. As I said before, I plan to mock up both options to see which looks better.

 

[Anonymous]

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.

 

[Anonymous]

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.

 

[das75]

Uncle Mike, talking something like the ppicture in thris thread on page 2?
http://reefcentral.com/forums/showthread.php?s=&threadid=1257783&perpage=25&pagenumber=2

 

[Anonymous]

Uncle Mike, talking something like the ppicture in thris thread on page 2?
http://reefcentral.com/forums/showthread.php?s=&threadid=1257783&perpage=25&pagenumber=2

Yes, but a modification of this.

1st and 3rd photos from top illustrate a slotted horizontal in-tank overflow pipe of teh type I plan to use

But I would modify the external plumbing shown in the 2nd photo from the top as follows:

1) I would add a gate valve to the drain leg coming out of the bottom of the "T".

2) I would add an elbow to the leg coming out of the top of the "T". The side leg of the elbow would be connected to a 2nd "T". The 2nd "T" would have vented cap on top and a 2nd drain leg coming out the bottom (draing to the sump). This is essentially a std Durso.

3) gate valve on 1st leg closed enough to force some flow out the top of the 1st "T", through the 2nd "T", and down the 2nd drain leg.

 

[das75]

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.