Because it still has to purge the air from the pipe. So it would have to build up enough to purge the air. In order to test it out u would need to close the valve on the syphon like it got clogged. That way the water builds up in the overflow box enough to purge the air from the open channel
Silent and Failsafe Overflow System
- Thread starter JohnL
- Start date
DougSupreme
New member
So, the plans have changed. I'm still planning on building the tank in the same configuration, but instead of glass, I've decided to use plywood. I'm 100% confident in my ability to make it work and look good.
I had too many people show concern with with building my first glass tank that large (wife was the deal breaker)
Still going to use a coast to coast overflow with the Bean animal drain setup.
Wish me luck. I'll probably start a build thread soon
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quick question here related to stopping/starting the return pump. Seems I have trouble getting the siphon going. When it's recommended to have the drain into the sump no deeper than 1/2" below the water level, is that when the system is running or when the return pump is off and the return line has siphoned down a bunch of water back into the sump?
DougSupreme
New member
I believe it's when it's running. You can drill a couple of small holes just above to running water line to help purge the air from the siphon line
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How is your overflow setup? Is it a interior box, exterior box or a ghost type overflow? To answer your question, it should be around 1/2” below the water level when the system is running.
From your first post it sounds like u have eighther a ghost type overflow or a exterior box. If that is the case & your stand pipes are actually inside the overflow box then u can try raising the open channel or lowering the syphon. What happens is the open channel can take on to much water & cause it not to build up enough to purge the air from the syphon. By having the open channel higher then the syphon it usually takes care of that.
That is one of the most common reasons but they have others that also make it hard to purge the air from the syphon. If u explain more about your system I’m sure we could figure it out without having to drill holes in the pipe. Drilling a hole can work but if it is setup properly it shouldn’t be needed.
From your first post it sounds like u have eighther a ghost type overflow or a exterior box. If that is the case & your stand pipes are actually inside the overflow box then u can try raising the open channel or lowering the syphon. What happens is the open channel can take on to much water & cause it not to build up enough to purge the air from the syphon. By having the open channel higher then the syphon it usually takes care of that.
That is one of the most common reasons but they have others that also make it hard to purge the air from the syphon. If u explain more about your system I’m sure we could figure it out without having to drill holes in the pipe. Drilling a hole can work but if it is setup properly it shouldn’t be needed.
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It's the eshopps eclipse L overflow. I've got the full siphon set up lower than the open channel already, was having issues dialing it in until I did that. I then added the John guest fitting and ro/di line to the top of the open channel and that's when the system really quieted down and is running awesome. Just can't seem to get it to purge after restarting return pump.
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That is one of the issues with those small overflow boxes. If I was u I would remove the pipe out of the bulkhead on the syphon & try it like that. That will tell u if that is your issue. With that small box u may find the open channel has to be quite a bit higher then the syphon for it to get enough pressure to purge the air. If the open channel starts taking water before the syphon purges the air then it will take a while for it to purge & may not at all.
Remove the pipe from the syphon bulkhead & see. U don’t need a pipe on the syphon anyway, so if it works better u can just put a strainer straight on the bulkhead.
If that doesn’t work then u have narrowed it down & can move on to the next thing to try
Remove the pipe from the syphon bulkhead & see. U don’t need a pipe on the syphon anyway, so if it works better u can just put a strainer straight on the bulkhead.
If that doesn’t work then u have narrowed it down & can move on to the next thing to try
Thanks for the suggestion. I'll give that a try and report back. Right now I have elbows on the open and siphon channels so I'll try removing from the siphon
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Str8linespeed
New member
Quick question. Getting ready to start up my tank. The hole in the top of the open channel piping elbow. Is it necessary to install a fitting and 1/4" air line? I have not installed that fitting and air line yet, but if I have to where does the air line go to? Is it just an open vent to the atmosphere?
DougSupreme
New member
The end of the air line gets mounted just above the running level of the overflow. If there is a blockage in the siphon, the water level in the overflow will rise, closing off the air line turning the open channel into a full siphon
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Str8linespeed
New member
Ok, thank you and that makes sense. I guess that brings me to the next question. When I tested my tank the water level was about 3/4-7/8 of the height of my open channel. Full siphon was under the water, and I had about 1" to the top of the emergency drain. Does that sound about right?
U really want the end of the airline to be just above the emergency. That way the emergency takes water before the open channel turns to a syphon. The main reason is because if the open channel syphons to quickly it can cause startup issues with the main syphon purging its air. The open channel may drain the overflow box before the syphon can purge its air. So the open channel should only syphon if both the syphon & emergency get clogged, so it’s kind of the last line of defense. It isn’t always the case & there is other factors, but it can be a issue. If I remember correctly u have a mm overflow box. In that case depending on your hieghts, u may be able to get away without a airline. If the hole u drill in the top of the U bend is slightly above the emergency & around 1” below the top of the overflow box then u can get away with not attaching a airline.
As far as water levels, it sounds ok but it’s hard to say without a pic or drawing. U will want the water level to be somewhere on the pass thru bulkhead. If the water level is below the bulkhead u will have a waterfall entering the box & it will be loud. Where u want the water level inside of the box will determine the hieght of the open channel. I would start with the top of the U bend on the open channel close to the top of the bulkheads
As far as water levels, it sounds ok but it’s hard to say without a pic or drawing. U will want the water level to be somewhere on the pass thru bulkhead. If the water level is below the bulkhead u will have a waterfall entering the box & it will be loud. Where u want the water level inside of the box will determine the hieght of the open channel. I would start with the top of the U bend on the open channel close to the top of the bulkheads
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Str8linespeed
New member
Thanks for the explanation.
Im using a modular marine ghost overflow. Tough to get behind the tank to take pics.
The first pic is full siphon, (90* st. elbow with a strainer),
2nd pic is from the other direction. Its a 1" pipe and a st. elbow and another st. elbow. making the U portion.
Yea, I edited my last post because I thought u had a mm box, so it may be worth taking another look at it. I think u can get away with not adding the airline & just leaving the hole in the top of the 90.
If u find that your syphon sucks air every once in a while u may need to add another 90 to make it a U bend. If it doesn’t suck air then it is fine how it is.
If u find that your syphon sucks air every once in a while u may need to add another 90 to make it a U bend. If it doesn’t suck air then it is fine how it is.
Str8linespeed
New member
Thanks for the info, I'll hopefully be starting it up today.
Str8linespeed
New member
Tank is online and I believe I have the BA for the most part dialed with the current piping in the overflow.
I have 2 questions.
1) My water level is about 1.25-1.5" below the rim of the tank. Just about a 1/4" above the lowest point of the slots in the weir. I have at least a full inch left until it dumps over the top of the weir. If I want to raise the water level in the DT, would I cut a longer piece of PVC to raise the open channel u bend higher in the overflow box, as well as raise my emergency?
2) Im not even close to going over the top of my emergency drain, but occasionally I will get a trickle of water that comes down that pipe. This happens about once every 45min. I've taken the pipe out of the overflow box, and twisted it back in but it still happens. Should I be concerned?
I have 2 questions.
1) My water level is about 1.25-1.5" below the rim of the tank. Just about a 1/4" above the lowest point of the slots in the weir. I have at least a full inch left until it dumps over the top of the weir. If I want to raise the water level in the DT, would I cut a longer piece of PVC to raise the open channel u bend higher in the overflow box, as well as raise my emergency?
2) Im not even close to going over the top of my emergency drain, but occasionally I will get a trickle of water that comes down that pipe. This happens about once every 45min. I've taken the pipe out of the overflow box, and twisted it back in but it still happens. Should I be concerned?
1- The water level in the dt is determined by the hieght of the weir. So there is no way to adjust that. By adjusting the valve on the syphon it will only affect the water level inside of the overflow box, not the DT.
2- It will probably make some noise every time water goes into the emergency. I would try to lower the water level inside of the overflow box. If a little water goes into the emergency on startup it isn’t a big deal & can even be expected, but I wouldn’t want it happening under normal conditions when the system is running. Where is the water level inside of the overflow box? How high is it on the pass thru bulkheads that hold the box on the tank?
2- It will probably make some noise every time water goes into the emergency. I would try to lower the water level inside of the overflow box. If a little water goes into the emergency on startup it isn’t a big deal & can even be expected, but I wouldn’t want it happening under normal conditions when the system is running. Where is the water level inside of the overflow box? How high is it on the pass thru bulkheads that hold the box on the tank?
Str8linespeed
New member
1)Gotcha, not much I can do about that, and the weir is as high as it could go anyways.
2)The water in the overflow isnt going high enough to get into the emergency tube, I think its going between the bulkhead fitting and pvc pipe. I still have about 2" until it gets to that height. Like I said its just a dribble of water coming out of that tube, about every 45 minutes or so. The water height on the pass through bulkheads are about 1/2 of the diameter. Kind of hard to tell, because I cant get my head back there.
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