building overflow in tank.

jwilson · Feb 5, 2014

i picked up a 58 gallon tank that had a corner overflow, and drilled bottom, but someone removed the overflow and capped the holes in the bottom. i'm fairly confident i can remove the caps without much of an issue, but i'm not sure how to go about building a new overflow. anyone built one that can offer a few tips?

ChrisKey · Feb 5, 2014

You can get a single piece of glass and have it just placed in the corner and silicone it in. There won't be any teeth but it works. Or you can just order the corner overflow kit and it will come with a plastic overflow that is curved or you can get then with 2 sides connecting at a 90 degee angle.

beaslbob · Feb 5, 2014

With a drilled tank the overflow is bacially just a durso stand pipe.

Really easy to build from pvc parts from lowes hd and so on.

jwilson · Feb 5, 2014

it looks like it had the L shaped overflow box in the left rear corner. i'd like to go back with that design if i can. i did some quick looking around on the net and found a couple designs that look like they would work, but i'm a "like to see it in person" kind of guy. i'm guessing i can buy black plexi or black acrylic at HD or Lowes so i have a actual box, then just plumb the return with PVC?

beaslbob · Feb 5, 2014

jwilson said:
it looks like it had the L shaped overflow box in the left rear corner. i'd like to go back with that design if i can. i did some quick looking around on the net and found a couple designs that look like they would work, but i'm a "like to see it in person" kind of guy. i'm guessing i can buy black plexi or black acrylic at HD or Lowes so i have a actual box, then just plumb the return with PVC?

it there just a hole at the bottom with no wall around the hole?

jwilson · Feb 5, 2014

it has two holes in the bottom. there are traces of silicone on the bottom where the walls were at one time, but they were removed at some point in time.

beaslbob · Feb 6, 2014

jwilson said:
it has two holes in the bottom. there are traces of silicone on the bottom where the walls were at one time, but they were removed at some point in time.

Hopefully you can find some "wall" the looks nice.

I also saw one system where they used a large diameter (6" or more) pipe to form the wall around the drains.

my .02

dictionaaron · Feb 7, 2014

Why not get lexan and cut your own. That is if you have any tools to do such things.

shovelrider · Feb 10, 2014

I have built a couple overflow boxes out of glass. They have no teeth and are "Herbie" style overflows.
No teeth = quiet and the best surface skimming.
I know glass is reef safe, I have heard plexi and lexan leech phosphates but I am not possitive on that.
My boxes are side drilled due to tempered bottoms, but if you can get the caps off the holes you got yourself an easily tunable "Herbie".

Once you get the caps off fit the bulkheads. If it was a store bought tank they will be different sizes.
If you want to follow the footprint of the original box, just measure the were the silicone is on the bottom of the tank.
For the hight, I just go about 1/8'' under the bottom of the tanks top trim piece. This hides the water level from view.

I would build the box first, let it dry completely and then install it in the tank.
**All the old overflow box silicone should be removed before installing new overflow box.
**If you use glass I would recommend tinted glass and use black silicone for a cleaner look.

Links to my builds so you can get an idea of how i built my overflows and how they look...

75 gallons

45 gallons

jwilson · Feb 10, 2014

mine has both holes in the bottom. that's the issue i'm trying to wrap my head around. don't want it to sound like a waterfall or a toilet flushing constantly.

shovelrider · Feb 10, 2014

Not at all...
If you use the Herbie style drain it will be silent and look like this...

Herbie Video

This is it more or less. It is very silent. You will have to run your return line over the edge of the tank after this mod because most likely one of your holes was a drain and the smaller one was for return. But the Herbie is quieter and safer as it uses a full siphon drain primarily and if it gets clogged it will fail over to the emergency pipe(the larger hole/pipe).

Themonsterisme · Feb 10, 2014

shovelrider said:
Not at all...
If you use the Herbie style drain it will be silent and look like this...

Herbie Video

This is it more or less. It is very silent. You will have to run your return line over the edge of the tank after this mod because most likely one of your holes was a drain and the smaller one was for return. But the Herbie is quieter and safer as it uses a full siphon drain primarily and if it gets clogged it will fail over to the emergency pipe(the larger hole/pipe).

This is exactly what I had to do to my 225 gal tank with a single overflow...had 2 different sized holes so I had to do a dual drain and ran my return up over the back of my tank...I'll get pics when I get a chance