# Herbie Overflow with Wet/Dry Filter



## rgrling (Apr 22, 2010)

I have a 90 gallon corner tank with a built in corner overflow (2 holes drilled into the bottom) that is connected to a wet-dry tower and sump.

Like many people, I am on a constant quest to make my setup as silent as possible. My 3 main sources of noise are (from greatest to least):


The rushing of water and air from the the drain pipe to the wet/dry tower
Gurgling from the top of the drain pipe at the water surface
Splashing noise as the water hits the drip plate 

I have experimented with various drain modifications, including the Stockman standpipe, the Durso standpipe, and the Hofer Gurgle Buster. Each of these is a variation of the same concept, and while they reduced the noises listed above, none of them have completed eliminated them.

Then, I came across the *Herbie Overflow*. In short, it relies on a fully submerged drain pipe to create a siphon that gets rid of noises 1 and 2. Here's a diagram:









From what I can tell, the top of the drain pipe (the pipe on the right, not the left) is submerged in tank water. The valve regulates the flow, and the bottom of the pipe is submerged in water in the sump, thereby reducing the speed of the water's travel through the pipe and the noise that causes. Water is then pumped from the sump back into the tank via a separate hose behind the tank (canister filter style).

Question is: Can you use the Herbie Overflow with a wet/dry filter? The drip plate and bio-balls section of the wet/dry tower is obviously suspended above the water level in the sump, so it would not be possible to submerge the bottom of the drain pipe. FYI, my sump does not have a separate water chamber for collecting water from the tank; unlike the MegaFlow models, there's just a hole at the top of the tower that leads directly into the drip plate.

I read somewhere that including a U-shaped pipe may mimic the submersion effect, but I'm not sure if that be effective. Here's a sketch I drew for reference:









Any ideas? I'm no expert when it comes to sumps or plumbing, so any advice would be greatly appreciated!


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## rgrling (Apr 22, 2010)

hello? anybody?


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## fkshiu (Apr 22, 2010)

Herbie himself (a user on Reefcentral.com) adapted and popularized this overflow system on a Megaflow overflow tank. In its most basic form, a Herbie overflow is even simpler than your diagram: just two standpipes, a tall and a short one, with a GATE valve under the shorter standpipe. A gate valve, as opposed to a ball valve, is vastly superior on a Herbie since it requires precision adjustment that a ball valve simply is not capable of. You are correct in that the valve regulates the amount of water flow into the sump. It should be adjusted so that the water level in the overflow box is just below the top of the taller standpipe. The taller standpipe should be the same height as the water entering the entering the overflow box (i.e. the lip of the overflow). The taller standpipe simple serves as an emergency backup in case the shorter pipe clogs.

As for your question of whether you can have a Herbie overflow with a Megaflow sump, the answer is that it will work fine as an overflow but it won't be silent (which is what you're after). The outflow of the shorter standpipe on a Herbie must be completely submerged for it to work silently. The outflow of the emergency pipe does not have to be submerged since it will be dry unless there is a blockage. Some people purposely leave the emergency outflow out of the water so that the resultant splashing alerts them to a problem should the emergency pipe ever be required to carry water. 

I don't think a u-trap would work since the water must still leave the pipe at some point and splash over the wet/dry grates causing noise.


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## gklaw (May 31, 2010)

Thanks for the post. I think I would modify this to have two overflow on the back/side of the tank. One will have strainer fully submerged and one at a higher level for overflow.

As to know in the sump. While not have the water dump into a filter pad or floss to take the noise out. Franklin is right that the P-trap as dawn is not adding anything to it. I am pretty sure you can cut the noise out by raising the outflow end high enough. However, that could create a trap that will require maintenance.

I would also use a full union gate valve - will cost more. I just cannot trust anything fully sumerged in SW. Sooner or later, you may need to take it out to clean the build-up or tiny coral growth in it.


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## Captured Moments (Apr 22, 2010)

I am not sure if the u-shape trap pipe to mimic submersion effect is going to work but it might..You can try it out. With the Herbie, it's like a full siphon and the trap can prevent air from getting pulled in. Regardless, you are running a wet/dry filter and no matter what you will still have noise coming from the water dripping from the drip plate and throught the bio media.


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