retrofitting a horizontal overflow to existing vertical overflow

RobertK

Premium Member
Hello out there,
I've got a 65 gal tank with a single vertical corner overflow. I want a horizontal overflow but can't drain and drill the tank. Has anyone installed an internal horizontal overflow that flows from left to right (or vice versa) and dumps into an existing internal vertical overflow? I really want to try this but prefer not to reinvent the wheel if possible.
Thanks,
Robert
 

graveyardworm

Premium Member
The problem is your tank is drilled through the bottom right? A vertical overflow like I believe your talking about needs to be drilled through the back. Are you having a problem with the overflow you allready have?
 

RobertK

Premium Member
Yes, the one I have is drilled through the bottom, and there is a square vertical column surrounding it up to the top of the tank. (typical corner overflow). The trouble is that I'm not getting enough surface skimming - lots of particles on the surface just going around in circles. The point is that I want to add a horizontal overflow without drilling the back of the tank.
 

Jasen Hicks

Premium Member
You could probably do this easily with the tank drained, but not with it full. I think the best way to do this would be to drain the tank, cut the exitsting box out, and clean all the silicone off the glass.

Next you would want to get a piece of ABS and shape it to an L that ran the length of the tank. You could cut teeth in it before this with a router and a 3/8" bit. Silicone it in. On the bottom part of the L that faces down you would need to cut a 1 3/4" hole and put a 1" uniseal in it, or a bigger hole and a bigger uniseal and run a piece of black PVC pipe to the bulkhead in the bottom of the tank. The uniseal will keep is straight and keep water out. Inside of the new box you would just put a T and a 90 like a small durso and it would work. THe only problem is you would have apiece of pipe running down the back, if you can live with that it will work.

Jasen
 

RobertK

Premium Member
Thanks for the suggestion. Sounds like a great idea. Not sure I'm up for draining the tank, though. I wonder if I could do some variation of your plan using the existing overflow as the vertical section and then tapping into it with the horizontal part. Then I'd only have to drain a foot of water out while I install the modification. What do you think?
Thanks,
Robert
 

Jasen Hicks

Premium Member
That might work, the only thing i would be hesitant on is the silicone fumes and accidently getting some in the water. Those fumes are actually nasty gasses that could suffocate the fish.

I have re-done some plumbing in the past and only let the solvent cure for about 2 hrs before allowing water to flow through the new path and a few of my corals withdrew for days. Fortunately nothing died, but it was a close call.

Jasen
 

RobertK

Premium Member
Wow, thanks for telling me that, Jasen. I didn't know that about silicone. I will definitely have to plan around that.

BTW, were you talking about using a sheet of ABS? Any advantage to using that over acrylic?

Thanks,
Robert
 

RobertK

Premium Member
Friends,

I am redirecting you to a similar post I started in the DIY section -

DIY Post

Please forgive me for posting the same questions in two different forums - I usually don't do that but I wasn't sure where to put it and now I think it makes more sense to have it under DIY.

I really appreciate your advice and hope you'll hop over to the other thread if you have any further suggestions.

Thanks,
Robert
 
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