Silent and Failsafe Overflow System
- Thread starter JohnL
- Start date
Shortening the pipe in the sump helps purge the air, but it usually isn't a issue unless it's submerged more then 1". U can also lower the syphon standpipe or raise the open channel standpipe. By doing eighther or both it will help the syphon purge the air. How u have the standpipes the water in the overflow isn't building up enough to purge the air because the open channel takes all of the water before it gets to that point.
From the looks of it the two standpipes are at the same hieght. In a exterior box like yours it's a good idea to have the open channel 1/2" to 3/4" higher then the syphon.
I use the standpipe on my syphon, but if u don't want to mess with it it is fine running how u have it now without the standpipe. Put a strainer on it & its good to go.
From the looks of it the two standpipes are at the same hieght. In a exterior box like yours it's a good idea to have the open channel 1/2" to 3/4" higher then the syphon.
I use the standpipe on my syphon, but if u don't want to mess with it it is fine running how u have it now without the standpipe. Put a strainer on it & its good to go.
John McGahern
New member
Hi Bean,
Great system but I do have a few questions for you before I start mine. 1. What is the purpose of the John Guest fitting? IS it just to make the connection airtight? 2. You used the tees with a cap I would assume because your system is external. Mine will be internal so could I just use elbows? 3. You state in your original article that all three drains are at the same height (with execption of the emergency being an upturned elbow) I've seen so many people on You Tube setting all 3 at different heights, why are they doing this?
Bean hasn’t posted in a couple months but I will see if I can help.
1. The fitting is mainly so the airline is airtight. If the syphon & emergency get clogged & the open channel becomes a syphon, u want it airtight. There are easier ways to do it rather then tapping a cap. The easiest way would to be to use 1/2” threads on airline fitting & use a bushing that goes from your plumbing size to 1/2”. Then the airline fitting will screw straight into the bushing.
2. Bean has a internal overflow on his setup that he had when he made this thread. With a internal box all u have inside the overflow box is the 90’s. His tees are on the outside of the tank at the bulkheads. U can use 90’s instead of the tees with caps on them, but I prefer to use the tees. I believe his reasons for the tees is to make connecting the airline fitting on the open channel easier. I think his main reason was if he ever needs to clean out the plumbing he could unscrew the cap & have access.
3. With a backdrilled tank & a interior overflow box, I have never had issues with the holes being drilled at the same height. I drill them all as high as possible without compromising the structural integrity of the glass. If u drill the syphon lower then the other two it’s just that much taller u have to make the overflow box. On a exterior box I make the syphon standpipe lower then the other two, but not a interior box with the bulkheads in the back glass. Of coarse it wouldn’t hurt to drill the syphon 1/2” or so lower then the other two holes & may help in some instances. The reason for the syphon to be a little lower then the other two is so the syphon has a chance to purge the air on startup. What happens in some instances is the open channel takes all of the water & causes the water not to build up enough to purge the air from the syphon. If plumbed correctly then this usually isn’t a issue. Using 90’s in the drain line instead of 45’s, have horizontal runs in the pipe or submerging the end of the pipe to far into the sump all make it more difficult for the syphon to purge the air. So if u do one or all of these things it may help to have the syphon drilled 1/2” or so lower then the other two drains.
John McGahern
New member
Thanks very much for your time Lsufan, really appreciate it!
You'll have to excuse my ignorance I've never plumbed a tank before. My present setup that I've had for 6 years was an old standard fresh water aquarium that I converted to marine using a hang on the back overflow box with a U-tube siphon to get the water to the sump. The tank was never drilled so I never had proper plumbing. Functional but that's it. So if you wouldn't mind I'd like to deal with one question at a time.
Is this airline tube something fancy or is it simply 1/4 r/o type tube?
Would I still need to use the John Guest fitting or are there other connection devices to make things airtight?
Thanks,
John
You'll have to excuse my ignorance I've never plumbed a tank before. My present setup that I've had for 6 years was an old standard fresh water aquarium that I converted to marine using a hang on the back overflow box with a U-tube siphon to get the water to the sump. The tank was never drilled so I never had proper plumbing. Functional but that's it. So if you wouldn't mind I'd like to deal with one question at a time.
Is this airline tube something fancy or is it simply 1/4 r/o type tube?
Would I still need to use the John Guest fitting or are there other connection devices to make things airtight?
Thanks,
John
1/4" will more then likely be fine but it depends on the size of the plumbing. For anything less then 1.5" I would use 1/4". For 1.5" I would use 3/8" but 1/4" would also work. I should have been more clear & called it by the right name but what I was calling airline fitting is the same thing as the John guest fitting. John guest is just a name brand, they have different manufactures. They are actually labeled as 1/4" O.D by 1/2" Nptf push connect fittings. The 1/4" would be the push connect side for the airline & the 1/2" would be the male threads. The trick is getting the treaded part of the fitting airtight. A bunch of people including myself just tapped the pvc cap on top of the tee & screwed the fitting in. It would be easier to just use a pvc bushing in the top of the tee. So say if u have 1.5" plumbing u would use a 1.5" by 1/2" bushing. Make sure the 1/2" side is female threads & the 1.5" side will slide straight into the top of the tee. Then the John guest would screw straight into that.
RO tubing will work but it can really be any polypropylene tubing, so nothing fancy. If u have some to tubing just use that, if not Home Depot sells poly tubing for really cheap
This is the fitting for the airline
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RO tubing will work but it can really be any polypropylene tubing, so nothing fancy. If u have some to tubing just use that, if not Home Depot sells poly tubing for really cheap
This is the fitting for the airline
Last edited:
John McGahern
New member
Thanks again. I should have mentioned that my new tank was drilled for a Beananimal set up but through the bottom, so my overflow AND plumbing will both be internal. With this in mind wouldn't I be able to just drill into the top of the 90 of the open line without the use of the airline and fitting? Would this not work the same way with the hole serving the same purpose as the open end of the tube. If a blockage occurs in the first Siphon line then wouldn't the water rise, cover the hole and then turn the open line into a full siphon much the same way? I would assume the only reason a tube line is used is because of the plumbing being external.
For some reason on my setup I cant seem to get the thing to run quiet. It seems that the open channel is very noisy. Lots of air and water mixed in the line (I can hear the water flowing through the Pipes). Also I have to keep the pump output down because as soon as I turn it up the emergency drain starts draining water and never stops. Turning the ball valve on the siphon line does nothing as well. I checked for to make sure there were no air leaks in the siphon line just be to be sure (none found).
Any advice on whats going on? I have attached a picture of my setup for reference. Its all 1" piping and I have a DCS-7000 Return pump.
Any advice on whats going on? I have attached a picture of my setup for reference. Its all 1" piping and I have a DCS-7000 Return pump.
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The open channel (the one with the airline) isn’t supposed to syphon unless both the syphon & emergency get clogged. So it is basically the last line of defense on a flood. So the end of the airline is supposed to be above the emergency drain. Without the airline the hole would be below the emergency drain so it wouldn’t work like it is intended to.
U can try & run it without the airline first & see if u have any issues. One issue that can happen is on startup the open channel may syphon because the hole gets covered before the actual syphon line can purge the air for the syphon to kick in. If it does this then the open channel would kick in & out of syphon as the water rises & falls in the overflow & cause the syphon line not to get going.
One way I suppose U could get around using the airline is by using a tee for the standpipe & extend from the top of the tee to where the cap is close to the top of the overflow box & above the emergency. That way the hole would be above the emergency, but it would need to be close to the top of the overflow box
In your picture the open channel is taking to much water. Eighther the water level inside the overflow needs to be lowered or the open channel raised. The open channel is supposed to only take a trickle of water. The larger the pipe the more it can handle but with 1” pipe it can’t take much more then a trickle & be silent. U want the water level to be right at a 1/4” or so above the bottom of the inlet on the tee. The inlet where the 90 attaches to the tee, about 1/8” to 1/4” above the bottom of the inlet.
Btw, a 1” syphon can handle between 1,500 to 2,000 gph. So u should be able to run that pump full blast after head loss on the pump & the syphon should be able to handle it. If u have to keep the pump turned way down then something isn’t right. I don’t know the size of your system or the head loss on the pump, but u more then likely don’t need to have the pump wide open, but it should be able to handle it if everything is working correctly
yea that is exactly what was happening. The problem was I couldn't adjust the water level inside the overflow box due to the full siphon not working properly. I had to purge out some air stuck in the siphon standpipe by disconnecting it from the bulkhead and letting all the water drain out of the over flow box. Once I replaced it back in, it worked fine. Hopefully this doesn't happen every time I turn off my pump. would I be better off just using 2 90s for the siphon instead of a 90 and a T fitting?
Ted_C
Active member
your full siphon outlet pipe is probably too deep underwater - preventing it from operating correctly. It cannot purge the air pocket if it's more than an inch underwater at normal operating levels.
This can be caused by the actual length of the pipe. it can also be caused by other variables like running the outlet into a filter sock and the filter sock is running higher than normal because it's clogged.
This can be caused by the actual length of the pipe. it can also be caused by other variables like running the outlet into a filter sock and the filter sock is running higher than normal because it's clogged.
Thats interesting.I thought the whole Idea of the valve was to control the water level in your overflow box. If I can not control the level how can I control how deep the siphon intake is? I guess I can raise the height of the siphon intake to be closer to the height of the bulkhead in the side of the tank. I don't run filter socks at all so that is deff not the problem.
Floyd R Turbo
Either busy or sleeping
He's referring to the drain end of your siphon line. This needs to be no more than 1" underwater
That makes sense. Yes I did adjust the length of that pipe because it was well below the 1 inch mark. Now it is 1-2 inches below the water line.
Floyd R Turbo
Either busy or sleeping
still might be too far. 0.5" to 1" below is all you really need/want
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