My external overflow is overflowing when return pump turns off

[Boycethefirst]

So I’m new to this whole reef tank thing but I plumbed a 125 gallon tank and put a eshopps overflow on. I drilled the tank and put two return hoses on each side of the tank. Another thing to mention is that I’m using the herbie method. So whenever I do a water change I gotta turn the return pump off and I do my thing. But then once I turn the return pump back on then the overflow will literally overflow... I believe it’s breaking the syphon somehow and it’s causing air to get in. I then have to turn the gate valves to completely open then I have to put the pvc pipe in then the water will reside then I’ll have to calibrate the syphon again. This process takes forever and I’m just wondering if I can change it somehow. Please let me know ladies and gents.

 

[Victor_C3]

Do you have holes drilled into the tops of the ‘U’s you have in the box?

I can’t tell from the pictures, but that’s what I did with mine and I have no issues.

 

[Boycethefirst]

Do you have holes drilled into the tops of the ‘U’s you have in the box?

I can’t tell from the pictures, but that’s what I did with mine and I have no issues.

Yeah I have one small hole on the secondary pvc U in the overflow box. Should I drill a small hole in the primary pvc U too?

 

[Victor_C3]

Yeah I have one small hole on the secondary pvc U in the overflow box. Should I drill a small hole in the primary pvc U too?

Absolutely. With air having no means to escape, water will never enter the primary drain.

If you get a gurgling sound and it bothers you, you could drill a larger hole and install small diameter airline tubing. Then run the tubing to somewhere else to draw in air.

I don’t have any noise from the drains themselves in my eshops eclipse overflow.

For what it’s worth, I see you raised the water level of the overflow by getting rid of the issued red pipe and replacing it with a taller PVC one. I figured out the same thing with my overflow, that you need the water level to be above the bulkheads connecting the two parts together to get rid of the trickling noise on the intake side.

 

[WvAquatics]

I don't have much knowledge. But I don't have a hole in my primary drain and it is doing all the work. From the picture it looks like your primary and secondary drain are both submerged? If so they are both pulling full drain right? So if you add more water then it's upto the emergency to keep up. If the secondary is only draining a little it picks up extra plus the emergency right? Correct me if I'm wrong

 

[WvAquatics]

NVM misread the original post. I see the issue.

 

[Dr Jimmy]

A full siphon should be silent and have no air. It looks like you're running two siphons and an emergency. Why not do bean animal?

 

[Victor_C3]

A full siphon should be silent and have no air. It looks like you're running two siphons and an emergency. Why not do bean animal?

You’re absolutely right about the siphon, but the issue I had with my overflow was that the momentum of the water going down the drain was enough to pull water out of the overflow box to the point that the water level drops below the U, causing all the water to fall out and losing the siphon when the return pumps are shut off.

I suspect the OP is having a similar problem.

 

[Dr Jimmy]

Sounds like a tuning issue? If you're pulling so much to break siphon

 

[WvAquatics]

Also just thought is your syphon drain gate valve closed at all? It should be wide open. But if Victor had the issue and fixed it definitely a way to fix your issue it's a win

 

[JCTReefer]

The purpose of the gate valve on the full siphon line is to tune it so the air is purged from the drain. If the valve is fully open, you’re going to get air mixed with the water. And it will be quite loud.
The full siphon should be dead silent, with only water in the line. Also your drains lines in the sump. Full siphon and secondary don’t need to be submerged any more than an inch or so in your bubble trap area. Especially the full siphon drain. A lot of times if your drains are to far below water level, it creates back pressure and makes it harder for the full siphon to get started. If you drill a hole in your primary, that completely defeats the purpose of a full siphon. Yes to having a hole drilled in the secondary. From the pic it looks like you have two siphon lines going. Theres really no need for a gate valve on the secondary. Some tuning will be necessary. I know you said herbie, but sure does look like it’s deigned for bean animal. I’m not sure what size the lines are on your overflow, but you’d be surprised at how much water you can push through a 1 inch drain at full siphon.
Here’s a video that explains the basics.

 

[Boycethefirst]

Absolutely. With air having no means to escape, water will never enter the primary drain.

If you get a gurgling sound and it bothers you, you could drill a larger hole and install small diameter airline tubing. Then run the tubing to somewhere else to draw in air.

I don’t have any noise from the drains themselves in my eshops eclipse overflow.

For what it’s worth, I see you raised the water level of the overflow by getting rid of the issued red pipe and replacing it with a taller PVC one. I figured out the same thing with my overflow, that you need the water level to be above the bulkheads connecting the two parts together to get rid of the trickling noise on the intake side.

hey victor, can you send me a picture of your set up? I’m curious on how the airline tubing will work. I know my primary tube is doing majority of the work and my secondary is barely doing anything which means it’s working properly. It’s just missing something...

 

[ca1ore]

You're not running a herbie, you're running a sort of bean. I couldn't see that anyone actually explained why your external box is overflowing …. maybe I just missed it. Since you have both the primary and secondary choked with gate valves, it takes a little while for the siphons to establish themselves. Normally the open channel secondary will handle the temporary flow. In your case, until the two siphons establish themselves, the only place for the water to go is down the emergency. If the emergency is too close to the top of the external box then the box will overflow.

You should remove one of the gate valves and have that drain operate as a secondary. then it will be able to handle the excess flow until the primary re-establishes the siphon. You probably need to lower the emergency. Clearly it cannot handle enough flow to actually be useful as an emergency.

Lastly, find a way to support the return plumbing. All that PVC is putting a lot of torque on the return bulkheads.

 

[Victor_C3]

hey victor, can you send me a picture of your set up? I’m curious on how the airline tubing will work. I know my primary tube is doing majority of the work and my secondary is barely doing anything which means it’s working properly. It’s just missing something...

Honestly, I’m not running any air tubing out of my drains, but I’ve heard that it will make them quieter. The noise doesn’t bother me, since I did something weird with the actual location of the external portion of the overflow box - I extended and placed it on the other side of the wall behind my tank. I died about 5” of 1.5” to the bulkheads that came with the box and added a second set of bulkheads to the external portion of the overflow.

I’ll take pictures when I get home in an hour or so.

 

[Victor_C3]

I hope that helps. Honestly, I don’t know why I even bothered to install a gate valve. I have enough flow going through the overflow that I have the thing wide open. I’ve put 2,800 GPH through the overflow, but to accomplish that even the emergency drain was pretty much at capacity.