Overflow piping heights

[mrlavalamp]

Plumbing an overflow and would like some thoughts on how high I have the two pipes.

Total tank height is about 30".

Both pipes are 1.5" sch40 pvc.

The left will be full drain but controlled with a valve to manage overall water height in the overflow. It comes to about 10" off the bottom.

The right will be 100% open with no valve, and plan to drill a small (1/4"?) hole in the top to keep it from going full syphon. as it sits, the top of this pipe is about 1" below the teeth on the overflow, and about 3" below the very top rim of the tank. Thinking worse case this would be enough to get a full syphon going on the durso and prevent the display from overflowing.

Tank volume is 180 gallons, I am planning a 2600gph dc return that I will likely run turned down some (also head loss). Return is through 2x 1" pipes through their own bulkheads inside the overflow and out through 2x 3/4 locline at the top (considering Y to 4 total 3/4" locline).

 

[dankaqua]

The left will be full drain but controlled with a valve to manage overall water height in the overflow. It comes to about 10" off the bottom.

The right will be 100% open with no valve, and plan to drill a small (1/4"?) hole in the top to keep it from going full syphon. as it sits, the top of this pipe is about 1" below the teeth on the overflow, and about 3" below the very top rim of the tank. Thinking worse case this would be enough to get a full syphon going on the durso and prevent the display from overflowing.

You lost me on this bit. So on the left pipe, there will be a valve (I'm guessing a gate valve?) and you want that valve to determine the water height inside the overflow box with the right pipe as a... backup?

 

[R.Weller]

It looks like you are attempting to combine both herbie & durso style drains from the pic. I would advise selecting one of the two & moving forward with that design. We are using the herbie style exclusively for our 300gal DT & it's brilliant. The design is outlined here:

Herbie Overflow Plumbing Guide for Quiet Reef Aquariums - gmacreef

The Herbie method can quiet down your aquarium drain and eliminate microbubbles. The guide includes helpful diagrams and explains each component.

gmacreef.com

In that design, only the left pipe is used as a syphon (controlled with a gate valve) & the right pipe remains dry as the backup. For dual overflows, you have redundant emergency pipes which is great.

With a 1" return & dual 1 1/2" drains, I don't see how there would be any way for you to overflow the display.

 

[mrlavalamp]

Thanks for the replies!

I definitely am mixing the two overflow systems.

I have actually changed it a little (and cleaned the glass so pic is clearer).

This is as it sits today.

I switched sides because the valve placement underneath was better. I lowered the top of the durso after watching a couple youtube videos where it seemed like water would raise several inches above it before a full siphon would develop and start catching up.

each of the 1.5" should have around 2000gph max flow capability and thinking my return should flow around 2100gph after head losses.

I was thinking that by tuning the full siphon and keeping the water level midway through the horizontal of the durso I would be able to keep it quieter.

Important to note, I have not glued anything inside the overflow and dont plan to. The pipes fit very tightly and I like the idea of being able to pop it all apart for changes/cleaning. Outside the tank, everything is glued as usual.

I originally tried to hard pipe the two 1" returns, but the bulkhead locations dont line up well enough. Hose was not my first choice, still not 100% happy with it, but I think it will work.

 

[R.Weller]

Good idea not to glue it. You should consider adding a screen over the herbie syphon pipe. It will collect debris, & you don't want that stuck inside the pipe at the gate valve.

Best success with the design.

 

[HOOPDEEZ]

You may want to put a tee in to replace the 90 with the hole in it. Or you could run a small piece of tubing up from it. Otherwise it will gurgle like crazy. Also make sure to have strainers on both, I prefer the threaded type and don’t tighten all the way. You could raise the main a bit if you wanted, it will drain more water into your sump if it’s lower. If that’s not a concern then It doesn’t matter. You’ll want to tune it so it barely flows into your durso

 

[JoshH]

Alright, I attempted to stay out of this one but I can't help it.

First and foremost, you are running a slightly modified Herbie Drain setup. No dursos in this setup atall. The only difference you have is a U bend at the top of the secondary/emergency pipe which is insignificant and can be placed on both pipes if you wish and run on Bean Animal drains as well. The true purpose of the U with a hole drilled in the top is to reduce the noise of the trickle that typically runs down this drain when the setup is running correctly. Also once the water level reaches the top of the U the pipe will go full siphon instantly. Which is FAR quicker than a standard straight pipe.

So, a couple of things that will improve your current setup.

1 - You need to raise your SECONDARY (not durso) drain up to a height closer to the top of the weir. In it's current state to run it as a Herbie drain your water level will run at the red line in the picture. This is by the looks of things, a roughly 6" drop for your 1800-2000 GPH to drop. I can only imagine what Niagara Falls sounds like in a house, but I would hazard to guess it wouldn't be far off. Raising the top of the U at the same level or even slightly higher than the bottom of the weir will eliminate this noise right off the bat (White line). This will bring your water level in the overflow MUCH closer to the weir where it should be (Green line).

2 - Vastly reduce or plug the bulkhead in the center of the overflow, unless this serves some other purpose other than bringing water into the overflow. You could reduce and add a flat strainer on the tank side which would still perform well if that was your intention. Shrinking or eliminating this bulkhead will force more water over the weir itself, this will pull more organics off the surface of your Display which is more ideal. Also as kindof mentioned above. If this hole remains in your overflow, and you turn off your return. Your entire tank will drain to the height of that bulkhead. I highly doubt that your sump is large enough to handle 2 thirds of your display volume...

3 - As mentioned above, add a strainer to the lower drain to help prevent anything from being sucked into the drain line with the valve.

 

[mrlavalamp]

Thank you each for your replies. I really do appreciate the feedback.

Josh, this exactly the kind of experience I am looking for.

1, I can absolutely raise it up to reduce the waterfall noise. My overflow

2, bulkhead has already been plugged, was waiting on a grey plug.

3, I have been waffling on the strainers. Seems lots of opinions/anecdotal experience splitting people between yes and no. I have only had smaller tanks previously, and they never had any sorts of strainers at all (3/4" or 1" drains, dont remember). When I asked a LFS dude what they use, he said they do not install strainers on any tanks, their own or customers because "the strainer clogs more than pipes/valves ever do" so that was the way I leaned.

 

[JoshH]

Thank you each for your replies. I really do appreciate the feedback.

Josh, this exactly the kind of experience I am looking for.

1, I can absolutely raise it up to reduce the waterfall noise. My overflow

2, bulkhead has already been plugged, was waiting on a grey plug.

3, I have been waffling on the strainers. Seems lots of opinions/anecdotal experience splitting people between yes and no. I have only had smaller tanks previously, and they never had any sorts of strainers at all (3/4" or 1" drains, dont remember). When I asked a LFS dude what they use, he said they do not install strainers on any tanks, their own or customers because "the strainer clogs more than pipes/valves ever do" so that was the way I leaned.

Honestly you can certainly run it without strainers (I don't run them myself). It's not the end of the world if you don't, afterall if something does get sucked in, you do have a secondary drain to protect you.

Glad you did plug the bulkhead, it would have more than likely caused headaches for you. Atleast IMO, If the holes already plugged, I would raise your secondary up about a half inch above the bottom of the weir and call it a day.

 

[dankaqua]

Have you considered a "bean animal" overflow? It's incredibly silent, easy to set and works very well.

Here's a 3D model:

(click on the image to load the model - allows you to zoom, rotate etc with your mouse ... doesn't work so well on a phone...)

The center pipe is the "emergency overflow".

The pipe on the left (with the clean-out plug) is the "trickle" overflow. A small amount of water runs down that pipe but there is no noise because the water flow is only a trickle.

The pipe on the right is runs at a "full siphon". The gate valve lower on that pipe is to tune the overflow.

Here's a video of the "bean animal" overflow in action (power off failure test):

 

[mrlavalamp]

I dont have 3 pipes to dedicate or I would have gone straight bean.

In the video you linked, I like how they put the tube on top of the elbow. Was kicking around just dropping a tube in the hole and silicone it in place, but the push connect is a more elegant solution.

thank you for the replies