# External Overflow Box and Herbie Drain Questions



## riggles17 (Jan 4, 2011)

Hey everyone,

My name is Rick and I've kept freshwater tanks for about 13 years now. Unfortunately I'm not switching to the salt side of this addiction just yet, but I would like to pick the community's brain a little.

When I say external overflow box, Herbie overflow, or BeanAnimal overflow, my friends and forum members on other sites think I have a third eye.. So I need your help for the plumbing on my new tank, please!

Its a standard 75 gallon tank, tempered bottom, and I want to run a full siphon to my sump. I've never done a Herbie or an internal/external overflow box before, so some of the questions I have are;

- Im going to be drilling the upper left corner of back pane of glass on the tank, if I go with an internal overflow box only, should I drill the bulkheads beside each other, or have one lower than the other?

- Is it better to go with an external overflow box in this case? I'm building my internal box myself, so if need be I can build an external as well.

- I have a bunch of glass thats never been touched with silicone or water from a 20g tank I took apart, could I cut it and silicone it to the back of the tank to make an external overflow box? Or is it better not to build your own external overflow and just stick with the internal on its own in this case?

Personally I like the idea of the external overflow box for both operation of the Herbie, but aesthetically as well, I think it looks a lot more professional  . I'm using 1" plumbing for the drains, yes I have my gate valve, and I'm planning on running a Herbie. It is a freshwater tank, and this is going to be overkill for the fish I'm keeping but it's going in my living room and I want it silent, or as close to silent as possible. I have a Quiet One 4000 as my return pump and my sump is already designed so I've got those covered already.

Any input would be great thanks.. and I know, I'm on the other side of the salt/fresh fence, but the help is much appreciated


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## riggles17 (Jan 4, 2011)

Anyone? I've decided to stick with an internal box, drill three holes and go with a BeanAnimal, but now I have a few questions about that since Im going to be using 1" plumbing. 

For the siphon on the BeanAnimal, why must I run a tee into a cap, why can I not just run the pipe into a 90 at the back, and forget the tee and the cap that resemble a standpipe? Seems pointless to me but is there a scientific reason for that? 

On my open pipe (the second emergency) I know I need to run a standpipe to have the airline come up and over. My question is should I drill all three of the bulkheads in a straight line, or should I have my main siphon a little lower than the other two? And where would I look to find that spigot that goes into the top of the PVC cap to attach the airline?

On the last pipe, again why must I run it into a tee? Seems pointless. All three lines terminate about 1" below the waters surface in the sump correct? 


My silicone questions have to do with building the internal overflow. Do I have to use a Momentive 108 or similar silicone for it? Or would a regular GE1 or some other silicone that is aquarium safe work for this? 

Thanks in advance, sorry for all the questions.

Rick


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## ruckuss (Jan 11, 2015)

I think people put the T with a cap so you can clean out the drain once and a while.


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## 4pokguy (Apr 27, 2011)

can't answer your question regarding the caps, but for silicone, you can use GE SCS1200.
Reefsupplies.ca, Canada Corals, and some other LFS carry it.


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## twobytwo (Oct 25, 2014)

riggles17 said:


> - Im going to be drilling the upper left corner of back pane of glass on the tank, if I go with an internal overflow box only, should I drill the bulkheads beside each other, or have one lower than the other?
> 
> - Is it better to go with an external overflow box in this case? I'm building my internal box myself, so if need be I can build an external as well.
> 
> - I have a bunch of glass thats never been touched with silicone or water from a 20g tank I took apart, could I cut it and silicone it to the back of the tank to make an external overflow box? Or is it better not to build your own external overflow and just stick with the internal on its own in this case?


Do you know how thick the glass is? If it's thinner, you may not want to risk drilling glass that wasn't meant for it. If you do drill, you may want more space than you think to reduce stress from the water pressure inside the tank. Have you thought about a coast-to-coast overflow box? I don't think the height of the holes matter as much because you can always compensate with the height of the pipe on the wet side.

I was into the idea of the external overflow, but I wasn't interested in the extra room i would need behind the tank to the wall. for me, it wasn't aesthetically pleasing.

You can make your own overflow box. You may prefer having one made though because you can get the size you want more easily along with things like teeth at the top to keep critters out of the box. I think there's a few guys on the board who work with Acrylic.If you were sealing a tank, I would agree with GE SCS1200 but if its just to keep the overflow box in place, I would think Silicone II is ok.

Do you already have the tank? I'm not the most experienced aquarist here but you sound like you're in the same place I was in about a year ago. I was going to drill a tank and put a setup together; but in the end I decided it was worth my time and patience to buy a Marine/drilled tank.


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## advanced reef aquatics (Apr 20, 2009)

3 x holes on 10mm not recomended


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## riggles17 (Jan 4, 2011)

twobytwo said:


> Do you know how thick the glass is? If it's thinner, you may not want to risk drilling glass that wasn't meant for it. If you do drill, you may want more space than you think to reduce stress from the water pressure inside the tank. Have you thought about a coast-to-coast overflow box? I don't think the height of the holes matter as much because you can always compensate with the height of the pipe on the wet side.
> 
> I was into the idea of the external overflow, but I wasn't interested in the extra room i would need behind the tank to the wall. for me, it wasn't aesthetically pleasing.
> 
> ...


I've drilled a couple tanks before without any problem, so that part I'm okay with  I have decided NOT to do the external overflow for a few reasons.. Glass thickness, doesnt seem to be thick enough.. Potential spot for leakage and I don't ever want water on the floor.. and finally the amount of space, the only part of the tank I can do it on would take up WAYYYY to much room for my liking. So. Bean Animal with an internal overflow box it is. I think I've got it all mapped out now properly. Once I have the actual tank, have it drilled and am test plumbing I will be back to this thread with pictures, so at some point down the road it may be a useful reference for someone, or give someone an idea on how it could've been done differently lol

Thanks for the input everyone, I appreciate it.


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## twobytwo (Oct 25, 2014)

advanced reef aquatics said:


> 3 x holes on 10mm not recomended


Rick, are you doing all 3 holes on the same pane? if you to the overflow box in a corner you could do 2 on one pane, 1 hole on the other...

Interested in your progress - tagging along.


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## riggles17 (Jan 4, 2011)

twobytwo said:


> Rick, are you doing all 3 holes on the same pane? if you to the overflow box in a corner you could do 2 on one pane, 1 hole on the other...
> 
> Interested in your progress - tagging along.


I was going to do them all in the upper left corner of the back pane of glass. It's a standard 75, thicker than 10mm for sure.


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