# 125gal. with holes drilled in.....fixable??



## sangi1a (Jan 11, 2009)

my neighbor has a brand new 125 gal tank for sale for $50. the only problem is that it has 4 holes drilled in the bottom. the are 2inches in diameter. i want a fw setup with no sump. can i patch the holes with silicone and pieces of glass? whats the easiest way?


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## clgkag (Mar 22, 2008)

Yep, just silicone a piece of glass over the holes. Just make sure you give plenty of overlap on the edges of the holes.


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## fishEH (Sep 15, 2008)

Thats a great find. 
I would put bulkhead fittings in there with plugs. Bulkhead fitting s are meant to be installed in the holes. Also, if you ever decide you want to use the holes for something all you have to do is remove the plug. If you silicone glass you'd have to drain the tank, use a razor to remove the glass and silicone, its a lot of work. 
You may want to make one of the holes a drain for expediting water changes. I have one in the bottom of my 75. I put a bulkhead in the hole and a ball valve below that. Then I hardpiped it to my sump pit. Cuts my water change time down by 3/4.


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## sangi1a (Jan 11, 2009)

the tank is not running. its brand new and never saw water. i was thinking of just getting (4) 5by5in peices of glass and just siliconing them straight in without removing the bottom glass. would that work? if so how thick should it be?

i didnt want to do bulkheads because they would be ugly sticking out of the sand.


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## broncbob (Dec 31, 2009)

The glass should be the same thickness of the bottom of the tank.


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## fishEH (Sep 15, 2008)

Unless you only have a quarter inch of sand the bulkhead won't be visible. The "bulk" of the bulkhead goes on the outside of the tank. Like I mentioned I have a bulkhead in the bottom of my tank for draining. Inside the tank there I have two 90's and a screen attached to the bulkhead. A cleverly placed rock hides it all. 
Siliconed glass pieces over the holes could also negatively affect resale value down the road. Although if you're getting the tank for $50 it may not be enough of a factor to worry about.


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## pistolpete (Dec 28, 2009)

man, what a steal. I wish I had neighbors like yours. Yep, glass siliconed on from the inside of the tank will work perfectly. Just make sure it's aquarium safe. The pressure of the water will hold the glass in place too, so no worries about anything ever failing.


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## wheatbackdigger (May 11, 2008)

Bulkheads and plugs. If you silicon glass in, you'll most likely regret it later. Why don't you just utilize the holes and make a wet/dry filter with a sump. Pretty simple, the holes are there already.


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## Mcdaphnia (Dec 16, 2003)

clgkag said:


> Yep, just silicone a piece of glass over the holes. Just make sure you give plenty of overlap on the edges of the holes.


Very bad idea. Seems logical enough but it does not work in practice. The glass patch does not give as much support to the glass as the bulkhead fitting does. I've repaired a bunch of these over the years. The bottom cracks under the patch then the tank leaks as the crack spreads out from under the patch. Use the 1" bulkhead fittings the hole is made for and you can close them off with plugs that screw into the internal thread of the fitting, or a cap on the outside threads if you prefer, but the plug lies flatter.


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## mg426 (Nov 24, 2009)

Use the bulkheads with a plug.


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## clgkag (Mar 22, 2008)

Mcdaphnia said:


> clgkag said:
> 
> 
> > Yep, just silicone a piece of glass over the holes. Just make sure you give plenty of overlap on the edges of the holes.
> ...


I have done it several times and have a couple years with no issues. If you use glass as thick as or thicker than the original bottom it shouldn't be an issue. However bulkheads are cheap and easy to come by. They are the what is originally meant for that so would probably be the safest choice.


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## csa dad (Jan 17, 2010)

dp bulk heads or like they said you will regret it in the future


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## mr.dark-saint (Jul 17, 2006)

Is the tank glass or acrylic? If glass I'd pass on it. I recon the half of ton of water would bust the bottom (maybe the seller arrived at this him self). I suppose you can buy a sheet of glass that would fit the bottom of the tank. I mean a sheet that would be about 1/4" smaller all around so you can drop a bead of silicone to make a new bottom.

If acrylic I'd buy a full sheet and do the same as a glass and use that liquid acrylic glue. Make sure you put some weight on the bottom. After it cures I'd flip it over and pour some liquid acrylic glue in the holes just to make sure there is no gaps. You don't have to fill it but have a nice seal.

Bulk head idea would be good for acrylic but for glass I would worry the bottom going out.


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## under_control (Jan 9, 2008)

mr.dark-saint said:


> Is the tank glass or acrylic? If glass I'd pass on it. I recon the half of ton of water would bust the bottom (maybe the seller arrived at this him self). I suppose you can buy a sheet of glass that would fit the bottom of the tank. I mean a sheet that would be about 1/4" smaller all around so you can drop a bead of silicone to make a new bottom.
> 
> If acrylic I'd buy a full sheet and do the same as a glass and use that liquid acrylic glue. Make sure you put some weight on the bottom. After it cures I'd flip it over and pour some liquid acrylic glue in the holes just to make sure there is no gaps. You don't have to fill it but have a nice seal.
> 
> Bulk head idea would be good for acrylic but for glass I would worry the bottom going out.


Why would it break? I don't get it. Tons of tanks are drilled on the bottom. This is common practice. It is perfectly safe. A 1/4" piece of glass would do nothing and a sheet of acrylic would cost a fortune.

Further, it is apparent you've never worked with acrylic. Acrylic bonding agents aren't glue and are really bad at filling in gaps. You need flat surfaces flushly mounted.


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## mr.dark-saint (Jul 17, 2006)

under_control - So I didn't get the correct "term" about the "bonding agent". As for the bonding agent being "bad filler of gaps". It's liquid. Like water. So it fills in better in the capilary movement. Sure I may not have sniffed bonding agent as much as you have. I have worked with acrylic.

Four 2" holes really does weaken the structure if the tank is glass.

Also the 1/4" was not the thickness of the glass but measurement. So there would be space around so one can run a bead silicone. As for a sheet of acrylic being too costly. I would rather pay a little than to deal with the cost of water damage.

So do go on with your attack on me to make yourself seem wise :thumb: .


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## fishEH (Sep 15, 2008)

The drilled holes in the bottom really shouldn't be a problem. Drilled holes are designed to be sealed with bulkheads, whether you plumb them or not.


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## Mcdaphnia (Dec 16, 2003)

sangi1a said:


> my neighbor has a brand new 125 gal tank for sale for $50. the only problem is that it has 4 holes drilled in the bottom. the are 2inches in diameter. i want a fw setup with no sump. can i patch the holes with silicone and pieces of glass? whats the easiest way?


The easiest way is to screw bulkhead fittings in place. No cutting glass, no super cleaning of the glass surface to be sure the silicone sticks. Simple as putting the lid back on the peanut butter jar.

By the way, if you were to resell the tank some day, a tank with glass patches will sell for less than the same tank with bulkhead fittings. Sort of like used cars. If a car has one green door and one primer door on a blue car, it will sell for less than the otherwise equal all blue car. Patches are minuses in the blue book. Bulkheads are options, to beat the analogy to death.


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