Silent and Failsafe Overflow System

[Mrramsey]

Getting glass cut need confirmation

Getting glass cut need confirmation

Hi Guys - Getting some glass cut for the overflow today. here are the dimensions I am using for the weir height and depth. What do you think?

The height is 4-3/4" and the depth 3-3/4". I am using a 1.25" x 1" 90 for the fittings. I am modifying the 1" side so it is more like a street fitting since I could not find one. It leaves me with about 3/4" between the bottom of the fitting and the bottom glass. There is about 1/2" to 5/8" between the front of the fitting and the front glass.

Any reason this should be changed? I also figured 1" below the top of the weir for the water line in the overflow. that puts the center of the 1" bulkhead at 3-1/2" from the top of the trim.

Does this all sound ok?

 

[Mrramsey]

I made some minor adjustments and made the weir 5" x 4" thus drilling my holes at 3-3/4" from the top of trim to center of hole. You can see I drew in a 1" Street 90 and a 1.25"x1" reducing 90 which is what I will use.

My water line in the DT will be just above the bottom of the trim by 3/16" +/- ant the level in the overflow should be at the top of the down turned elbows.

 

[Mrramsey]

I made some minor adjustments and made the weir 5" x 4" thus drilling my holes at 3-3/4" from the top of trim to center of hole. You can see I drew in a 1" Street 90 and a 1.25"x1" reducing 90 which is what I will use.

My water line in the DT will be just above the bottom of the trim by 3/16" +/- ant the level in the overflow should be at the top of the down turned elbows.

No one?

 

[uncleof6]

The open channel will have bubbles, the siphon should not. almost always the air is being sucked in at the top, slightly closing the valve raising the water level will help. If the bubbles are pea size or larger it's from the opening, if they are micro or very tiny it could be a slight leak which are normally near the bulkhead, but may be anywhere. fortunately those micro leaks don't really make any impacts to the drain function and you can live with them if you choose.

The open channel should be kept within its laminar flow capacity, or most often—below. Laminar flow is water flowing on the walls of the pipe with CALM air in the middle. E.G. the air is not in motion, therefore air is not sucked into the standpipe. If the open channel is sucking in air, the system is adjusted wrong, and the flow through the open channel is too high.

When the system is adjusted properly, there should be no bubbles coming from the drains at all. If there are bubbles coming from the open channel, the system is not adjusted properly. Even an air leak in the open channel will not cause bubbles. (The open channel is one large air leak...) There is no reason to have bubbles coming from the open channel.

Therefore, the only reasons for bubbles from the drain lines are (properly adjusted): air leaks in the siphon. Built and adjusted properly, the odds are more than likely the bubbles are coming from a misadjusted skimmer.

With 150 systems converted (out of ~300) to this drain system, it is very predictable; a very consistent drain system, from tank to tank. I have zero noise, and zero bubbles. There are a finite number of issues that can arise, and no mysteries. If you have bubbles, you did something wrong.

There are probably more ways I can think of to put it, but that should suffice.

 

[uncleof6]

No one?

The point of reference is the top edge of the glass not the top of the trim. The top edge of the glass averages 1/2" below the top of the trim, but don't count on it.

From the top edge of the glass, for a 1" bulkhead, the hole needs to be 1.75" to the top edge of the hole, plus the width of the flange (to be on the safe side.) This is the safety consideration. Without personally measuring the fittings you have in hand, it cannot be determined what adjustments need to be made to the dimensions, to get the water level where you want it. Generally for the size plumbing you are using, the box ends up 6+" top to bottom. Sounds like you are trying to squeeze it in there...

 

[Mrramsey]

The point of reference is the top edge of the glass not the top of the trim. The top edge of the glass averages 1/2" below the top of the trim, but don't count on it.

From the top edge of the glass, for a 1" bulkhead, the hole needs to be 1.75" to the top edge of the hole, plus the width of the flange (to be on the safe side.) This is the safety consideration. Without personally measuring the fittings you have in hand, it cannot be determined what adjustments need to be made to the dimensions, to get the water level where you want it. Generally for the size plumbing you are using, the box ends up 6+" top to bottom. Sounds like you are trying to squeeze it in there...

Based on my drawing which is what I have. The edge of my flange will be 1-3/4" from the edge of the glass thus the edge of my actual hole will be ~2-1/4".

 

[uncleof6]

Based on my drawing which is what I have. The edge of my flange will be 1-3/4" from the edge of the glass thus the edge of my actual hole will be ~2-1/4".

Should be fine, however, since speers is different from lasco is different from nibco is different from charlotte... get the parts in hand and measure everything before finalizing anything.

 

[Mrramsey]

Yes I have them on hand. Schedule 80 bulkhead forgot the manufacture. Just wanted to confirm the location. I know there was a post about it but damned if I could find it... thanks uncle!

 

[jncasey]

Uncle,

Based on your drawing previously posted, I can follow this example with the only correction being that the centerline of the 1" bulkhead(s) should be 3.75" from the top edge of the glass, not 2.75"? Please confirm. Also, bulkhead spacing should be 1.5" apart? Are all three bulkheads on the same centerline? I wanted to make sure the dry emergency overflow bulkhead followed said centerline as well....(elbow just facing upwards).



Thanks!

 

[jncasey]

Uncle,

Edit:

Wrong photo previously posted. Please refer to this photo:

 

[jncasey]

Bump.

I'm having the tank drilled and internal c2c weir installed Monday.

 

[uncleof6]

Uncle,

Based on your drawing previously posted, I can follow this example with the only correction being that the centerline of the 1" bulkhead(s) should be 3.75" from the top edge of the glass, not 2.75"? Please confirm. Also, bulkhead spacing should be 1.5" apart? Are all three bulkheads on the same centerline? I wanted to make sure the dry emergency overflow bulkhead followed said centerline as well....(elbow just facing upwards).



Thanks!

Minimum safe distance is 2.75" from the edge of the glass to the centerline of the hole, for 1" bulkheads. They can be farther down, making the waterfall into the overflow higher. 3.25" is a good number, but 3.75" is a bit overkill.

2.75" can have a varience depending on the dimensions of the elbows you actually have. (wall thickness.) The safe spec says: 1 hole diameter from the edge of the glass, to the top edge of the hole, and 1 hole diameter from hole edge to hole edge. (2 hole diameters hole center to hole center) I use Speers fittings exclusively, as they are the most consistent. You want the waterline in the overflow to be right around the top of the downturned elbows.

Incidentally, I pretty much used micrometers to come with these minimum dimensions...

 

[garyinco]

If you are going through the trouble of drilling another hole, then you may want to use the system as described in this thread. 1 siphon, 1 open channel and 1 backup. The smaller of the 3 holes needs to be the siphon.

This was mentioned waaaayy back before the thread was split...

I have a tank on order (pics of the tank model, a Neo 105 from Deep Sea Aquatics) that already has four holes drilled (two 1" and two .75").

So based upon Bean's quote I should set the siphon channel to be one of the .75 holes?

I will be using the other .75" hole for the return. I plan to be returning about 420gph.

There is another thread on here where a guy set his up a little differently. See this thread post for a picture. He used one of the 1" holes for his siphon channel and one .75" hole for the emergency channel. He says it works and is happy.

I guess I'm just concerned a .75" siphon channel will run at max and too much water will need to run down the open channel creating noise and defeating a major benefit of the BA design.

Thanks in advance for any comments.

 

[RicoJ]

Is there a formula on how tall the weir should be? I have seen some tall weirs in the past and don't understand why there would be such a need fir such tall ones. I would like to make the weir as small as possible as I want to maximize tank space in my 40 gallon breeder.

 

[Floyd R Turbo]

Not sure exactly what you mean by "tall".

The formula for flow rate however is:

Q = 288 * C * L * H^(3/2)

Where

Q = flow
L = length of weir
H = height of water over top of weir (or up from bottom of notches)
C = discharge coefficient.

For a straight weir (no teeth/notches) then C = 1.0

For an overflow with teeth (1/4" wide notches), then C = 0.55 tp 0.60, and L = sum of all gaps (number of 1/4" notches time 0.25).

If you know your target flow rate Q, then you just solve for H

H = (Q / (288 * C * L))^(2/3).

 

[RicoJ]

Wow that's some formula. Sorry by how tall I mean the vertical height of the overflow box.

 

[uncleof6]

Wow that's some formula. Sorry by how tall I mean the vertical height of the overflow box.

No there is no formula for determining the height (how tall) the overflow box should be. The only criteria is the bottom of the overflow should be
~3/4" or so below the bottom of the down turned elbows, and the top edge should be even with the trim on the outside of the tank, to hide the water line. On a rimless, figure 1" down from the top edge of the glass. Get out your measuring stick ...

 

[Jimbojames]

i wanna run a REEFLO SNAPPER/DART HYBRID, on my bean animal over flow, is this ok? i have 3 1in holes going into 1.5 pvc?

 

[uncleof6]

i wanna run a REEFLO SNAPPER/DART HYBRID, on my bean animal over flow, is this ok? i have 3 1in holes going into 1.5 pvc?

Depends. Myself I would not do it. Not with 1" bulkheads. No sense limiting the flow to ~1500 gph at best with a normal drop height, with a pump capable of around double that...If not going that high, get a more reasonably sized pump suited to your system.

 

[BeanAnimal]

FWIW, I run a ReeFlo dart on the system, as published

I had a Snapper for some time, but wanted more flow. I keep meaning to put the new DC pump on the return but never get around to it, so for now the Dart it is.