On my old 50, I used smoke glass for my C2C. I hated it from day one for the same reason. After the coraline grew on it, it wasn't so bad, but for a year, not so much. I have a 120 glass now, and I used black acrylic without issue. It bows a tiny bit from the water pressure in the tank, only noticeable I you look through the end of the tank. The bowing ould be taken care of if I put small braces in the overflow. I like the acrylic much more. I attached it with silicone and havent had any issues, and do not anticipate any.
Silent and Failsafe Overflow System
- Thread starter JohnL
- Start date
gregjonesonline
New member
great thread, thanks for the ideas!
BeanAnimal
Premium Member
gregsones... The idea here is to participate in discussions, not post one liners in hopes of reaching 50 posts ande being granted access to the selling forums. You will find that you wil lbe starting back at 0 in the blink of an eye...
wonrib00: For a glass tank, you really should be using a glass overflow. Silicone and acrylic don't bond well, and a failure (even a small one) would allow the tank to drain to roughly the bottom of the overflow box.
wonrib00: For a glass tank, you really should be using a glass overflow. Silicone and acrylic don't bond well, and a failure (even a small one) would allow the tank to drain to roughly the bottom of the overflow box.
BeanAnimal
Premium Member
The valve on the siphon standpipe needs to be adjusted to balance the system...
The description on my site is a good starting point for a basic overview of the sytem, operating principle and adjustment.
http://www.beananimal.com/projects/silent-and-fail-safe-aquarium-overflow-system.aspx
The description on my site is a good starting point for a basic overview of the sytem, operating principle and adjustment.
http://www.beananimal.com/projects/silent-and-fail-safe-aquarium-overflow-system.aspx
Dotterer
New member
I made it through!
This was a long - but great thread to get through. I think it took me 2 months of 1-2 pages at a time during my down time.
So I'm finally getting the glass and PVC ready for my 125, and I'm doing an internal coast to coast/external combo. (Thanks Uncle for the image of the placement, btw.)
My questions are:
1) Since I'm coming through the bottom of the external, and using 1.5" bulkheads, should I still use the reducer to get to 1"? Does the limited input that then opens up play a role in the design? Or does a simple 1.5" all the way to the sump work just as well?
2) How high should the standpipes be? It seems that there is a height to the standpipes above the sanitary T that makes it stick up above tank, how long should that piece of 1.5" pipe be?
Many thanks both to Bean and all of the people in this thread who have gone out of their way to help folks - I really appreciate your assistance, and look forward to the next step!
This was a long - but great thread to get through. I think it took me 2 months of 1-2 pages at a time during my down time.
So I'm finally getting the glass and PVC ready for my 125, and I'm doing an internal coast to coast/external combo. (Thanks Uncle for the image of the placement, btw.)
My questions are:
1) Since I'm coming through the bottom of the external, and using 1.5" bulkheads, should I still use the reducer to get to 1"? Does the limited input that then opens up play a role in the design? Or does a simple 1.5" all the way to the sump work just as well?
2) How high should the standpipes be? It seems that there is a height to the standpipes above the sanitary T that makes it stick up above tank, how long should that piece of 1.5" pipe be?
Many thanks both to Bean and all of the people in this thread who have gone out of their way to help folks - I really appreciate your assistance, and look forward to the next step!
Landsailor
New member
I actually had person tell me that LeeMar tanks were better than Visios because Visio builds glass overflow boxes and then puts the acrylic over them. LeeMar just uses acrylic to glass because "they know what they're doing".
The laws of physics are different in different parts of California.
autodave
New member
LeeMar uses a proprietary silicone to bond acrylic to glass (they would not tell me kind of silicone it was). They have been using acrylic for external overflows for some time now.
You would hope that with ONE INCH thick black acrylic you better not be able to see through that!
But what about 3/8" black acrylic?
With my glass tank, I'm going with black "Graylite" glass for my internal weir but I'm sure it's more translucent than opaque.
I will be fabricating the external overflow to be smaller than the overall dimensions of the internal weir to hide its edges on the back glass. The back glass itself will be painted black.
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Ted_C
Active member
Hey all - I have a question on this and the open channel functionality.
I've set-up my design so that I have three drains - from left to right - one is 4 inches from the edge of the tank, second is in the middle of the tank and the third is 4 inches from the right of the tank.
My siphon is on the left, emergency in the middle, open channel on the right.
All three overflows are tied together into 1 1/2" pvc that drains into the sump with 1/2" rise per foot of run (drains to the right - so nearly underneath my open channel).
The overflows sit inside my coast to coast.
I have no problems handling the eheim 1262 - my siphon's valve is letting through approx 80% of the water which keeps the water in the overflow just below the top of the open channel (maybe 1/2" below the open channel).
The problem I'm having is - when the air inlet on the open channel get's submerged - it's not emergency siphoning anymore. I did have this working when I first had it running (the overflow box would be drained if the air inlet on the open channel got submerged). Now I submerge the air hose on purpose and nothing happens.
I can blow through the air inlet and it bubbles back out of the open channel in the overflow box.
Even removing the pvc cap and air inlet and blocking the entire pipe has no effect. Blowing through the air hose and blocking the cap doesn't produce any audible leaks.
I think the issue is - since I've tied all three drains together into a single pipe into the sump - one of the following is happening:
A siphon is occurring in my one main pipe into the sump (wouldn't seem possible with the open emergency center drain). This prevents the open channel siphon from ever occurring.
My emergency center overflow is preventing the open channel from pulling a siphon.
I've set-up my design so that I have three drains - from left to right - one is 4 inches from the edge of the tank, second is in the middle of the tank and the third is 4 inches from the right of the tank.
My siphon is on the left, emergency in the middle, open channel on the right.
All three overflows are tied together into 1 1/2" pvc that drains into the sump with 1/2" rise per foot of run (drains to the right - so nearly underneath my open channel).
The overflows sit inside my coast to coast.
I have no problems handling the eheim 1262 - my siphon's valve is letting through approx 80% of the water which keeps the water in the overflow just below the top of the open channel (maybe 1/2" below the open channel).
The problem I'm having is - when the air inlet on the open channel get's submerged - it's not emergency siphoning anymore. I did have this working when I first had it running (the overflow box would be drained if the air inlet on the open channel got submerged). Now I submerge the air hose on purpose and nothing happens.
I can blow through the air inlet and it bubbles back out of the open channel in the overflow box.
Even removing the pvc cap and air inlet and blocking the entire pipe has no effect. Blowing through the air hose and blocking the cap doesn't produce any audible leaks.
I think the issue is - since I've tied all three drains together into a single pipe into the sump - one of the following is happening:
A siphon is occurring in my one main pipe into the sump (wouldn't seem possible with the open emergency center drain). This prevents the open channel siphon from ever occurring.
My emergency center overflow is preventing the open channel from pulling a siphon.
uncleof6
Active member
Your problem, and it is a HUGE deviation from the design of this system is: All three drain lines join a common pipe. This causes interaction between the three lines, and therefore creating a system that has no chance of operating properly. The three drain lines need to separate completely for the system to function properly. The only intended interaction is between the siphon and open channel, and that interaction occurs at the top end, not at the bottom end. The dry emergency is allowing air into the line, breaking the siphon at the bottom end--essentially making all the pipes open channels.
Make all three drain lines separate and distinct entities, from the tank all the way to the sump. Avoid any horizontal runs. I believe that will solve your problems.
Make all three drain lines separate and distinct entities, from the tank all the way to the sump. Avoid any horizontal runs. I believe that will solve your problems.
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Dotterer
New member
Any Thoughts?
uncleof6
Active member
1) Depends on your flow rate. Unless you are wanting above 1500 gph or so (depending on the length of the drop) you don't want the 1.5" bulkheads either. At lower flow rates, there seems to be a starting issue with large bulkheads. 1" bulkheads, with 1.5" pipe, is a better idea, unless you have a short drop and targeting a relatively high flow rate > 1500 gph (1" bulkhead will probably do that with 1.5" pipe to keep the friction loss down) with around a 36" drop. 24" drop may be iffy. 1" bulkhead max theoretical is ~1660 gph with a 24" drop. So what you need depends on your flow rate, and your drop. Without that info, there is not much of an answer.
2) Long enough to get a screw cap (use an adapter.) Beyond that, it does not matter. So from top of tee, to adapter, cap screwed on. Just enough pipe to get a good glue joint between the tee and the adapter. The adapter can be seated on the top of the tee.
2) Long enough to get a screw cap (use an adapter.) Beyond that, it does not matter. So from top of tee, to adapter, cap screwed on. Just enough pipe to get a good glue joint between the tee and the adapter. The adapter can be seated on the top of the tee.
Dotterer
New member
Thanks, Uncle (and thanks for the answer on the second point too.)
I'm returning to the hobby after 20 years (was an Underground Filter back then) so will be my first sump. Seems to be a lot of different opinions on flow (sump and inside both), so I thought I'd go 1.5 to keep options open. I'm still picking a pump for the return too - but figured a 10X would be 1250 so if I did want to go above that, would be safe. The concerns on starting with 1.5" bulks have me concerned as well, though..
However, with the external overflow, it seems like it would be a lot easier to go to the 1.5" sani-tee. With the original design, the t is on the outside, so the reducer to 1" only happens once, but on the external, this will be coming up from the bottom. So I'd either have to find 1" sanitary tees, or have 1.5 on the drop, then to 1" for the bulk" and back to 1.5 sani, or am i missing something?
Thanks...
uncleof6
Active member
Well they don't make 1" sanitary tees. Charlotte Pipe and Foundry do make a 1.25" sanitary tee. Flowing ~1250 gph, is not much really. Easily handled (or close enough) with a 1" bulkhead, and ~ a 2' drop. At three foot, it would do better than that.
The bulkhead and length of the drop determine the flow capacity, the pipe size is a question of friction loss. Larger pipe allows the bulkhead to flow closer to its theoretical limit at a given drop. (1660 @ 24" drop)
If you use 1.5" bulkheads, the valve will be closed quite a bit, as the theoretical limit for the 1.5" bulkhead at 24" would be roughly double that of the 1" bulkhead, or better.
As for the concern for a relatively low flow rate on a large bulkhead causing a starting issue, it is much anecdote at this point. There have been sufficient "complaints" with this configuration to warrant a heads up, but it is not written in stone.
I am tempted to say that a good compromise would be 1.25" inside the external, 1" bulkhead, 1.5" pipe from the bulkhead down, and you should be fine for a target of 1250 gph. You would probably get close enough with 1" all the way. Sanitary tees are not required, they do give a little less turbulence at the start of the drop.
Dotterer
New member
Yep. That's the issue.
I guess I don't quite understand the bulkhead size. I mean, in an external overflow, the bulkhead occurs AFTER the sanitary T, not before. So it seems like restricting that would not make a lot of sense (and would change the original design). It seems if you wanted to most closely approximate the original design, you would use a 1.5" bulkhead, and simply drop from 1.5" to 1" on the elbows....
uncleof6
Active member
Yep. That's the issue.
Not really an issue at all. Sanitary tees, as has been stated countless times, are NOT required.
The bulkhead size determines the flow capability of the drain system. It sets (along with the length of the drop) the max theoretical flow through the bulkhead. The pipe size is a question of friction loss, or "how close you can get to the max theoretical flow rate." Doesn't matter where the bulkhead is, it still sets the flow rate--unless the pipe is smaller than the bulkhead. Then the pipe size sets the flow rate.
So if you were to put 1" pipe, on a 1.5" bulkhead, you would be limited to what a 1" bulkhead would allow. Simple.
To approximate Bean's system, 1.25 inside the external box, 1" bulkhead, 1.5" pipe after the bulkhead. Bean went 1.25" > 1" > 1.5". Understand? 1.5" pipe and bulkhead has too high a flow capability for your system: ~3180 gph (after friction loss approximately.) That is pointless, and may cause a starting issue.
Dotterer
New member
Not really an issue at all. Sanitary tees, as has been stated countless times, are NOT required.
To approximate Bean's system, 1.25 inside the external box, 1" bulkhead, 1.5" pipe after the bulkhead. Bean went 1.25" > 1" > 1.5". Understand? 1.5" pipe and bulkhead has too high a flow capability for your system: ~3180 gph (after friction loss approximately.) That is pointless, and may cause a starting issue.
There is a difference - on an external overflow the bulkhead occurs AFTER the tee, not before. With Bean's original design, there is a vertical bulkhead, where the restriction (the 1") occurs prior to the T. In an external, there is a horizontal bulkhead, that the drop pipe comes up through, and the tee is inside the box, not outside.
So yes, Bean went for a 1.25" > 1" > 1.5"
But an External would be
1.25" > 1.5"
. . . . . . |
. . . . . . V
. . . . . . 1.5"
Where the Bold/Italic is the bulkhead. (hopefully my formatting here works)
I don't understand why you would want to restrict the flow after tee in this manner. It would basically turn then 1.5" drop in the original design into a 1"
pipe.
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