# Concrete bottom tank.



## A_USER_NAME (Apr 26, 2013)

I just picked up another tank pretty cheap. Previous owner cracked the bottom pretty good so they decided to lay the bottom with concrete reinforced with fiberglass. It drips very slowly but I want it water tight. (Its leaking because the water leaches throught the concrete, leaking through the cracks in the glass in some spots) One option I though of was to put a layer of silocone over the surface of the concrete, another option was to layer the bottom with a pond liner and seal the edges with silicone.

Maybe bust out all of the concrete and reinforce the glass with plexiglass along the cracks? Its an 80 gallon corner tank so I dont think that would work so well.

I have tried sealing all of the leaks as best as I could but it didn`t work, I am about to break out the bottom and have a glass company or something make me a new bottom. :x


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## A_USER_NAME (Apr 26, 2013)

Im going to try the trash bag, Layer the bottom and seal the edges, hopefully it works!


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## ratbones86 (Jun 29, 2012)

i would either ditch the tank of have a new piece of glass cut and redo the bottom if you can get the concrete out of the tank lol


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## jakekersley (Mar 25, 2013)

I'd buy a new tank, I'd rather have minimal chance of a tank leaking. I imagine the drama of it leaking once established. Can you post some pictures?


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## BillD (May 17, 2005)

If I was going to try and save the tank, I would cover the concrete with Dryloc, and seal the edges with silicone. There is still a risk, but Dryloc is very good at sealing concrete, which is it's purpose. As well, I would support the entire bottom with styrofoam.


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## PreposterousFish (Jan 8, 2013)

I would ditch the bottom pane. Take apart the tank and clean it up real good. Then use plywood as the bottom. Like the video below.


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## rgr4475 (Mar 19, 2008)

Not worth the work IMO. Sounds like a complete mess. But if you go ahead with it, please post up some pictures. I am curious to see what it looks like in it's current state.


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## A_USER_NAME (Apr 26, 2013)

Unfortunately I am in New Jersey at the moment for training, but when I get back home in the next month I will post some pictures.

The original glass bottom is under the cement, so it should be supported well enough. I was considering buying some liquid plastidip and pouring it over the cement which would seal it. I would also line the edges with silicon to be safe.

I will be sire to post pictures with whatever I end up doing. Though I will only have a few days to work on it, once I get home from training I will only have a few days before I deploy. After that its up to my wife to fix it.

Thanks for the ideas everyone!


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## A_USER_NAME (Apr 26, 2013)

I was reading on drylok and have a question. Does it dry hard to somewhat flexible?


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## joemc (Sep 23, 2012)

I collected a 6x2x2ft tank from a friend afew years back, it was not in the van 5 minutes when it slid going around a corner cracking the bottom, I spent ages trying this that and the other to get a quick fix, silicon, patching the crack with more glass etc, nothing worked when I tested it, in the end I stripped off the damaged base and replaced it with a new sheet of glass, only then did I feel confident that the tank would hold water.
If I was to try work with what you have the only shortcut that I can think of that may work is to coat the inside bottom in G4 Pond Selant, I have used this on many pond constrution jobs and never had a leak, but it needs to be applied as per the instructions.


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## DanniGirl (Jan 25, 2007)

A_USER_NAME said:


> I was reading on drylok and have a question. Does it dry hard to somewhat flexible?


It's a sealant with a consistency similar to drywall mud (joint compound). It's not flexible.


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## jcabage (May 29, 2012)

I'll begin by saying I'm pretty bad at this myself... When considering a project such as this though, oftentimes the time spent goofing around with this and that (much like joemc said) can be more valuable than a tried and true, yet more expensive solution.

To rephrase, the option that is a more expensive fix (that gets it right the first time) usually outweighs tinkering and frustration over 3 weeks of work, at least at our house :lol:

That being said, you could try drylock, plywood, this and that, but I would say if you want peace of mind, just get the glass cut and grab a bottle of silicone!


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## A_USER_NAME (Apr 26, 2013)

Thanks for the replies, I would get a new sheet of glass but I don't think I'll have enough time to get it done. I'll call around, but if drylok would work for 7-8 months I would be fine with that. I can completely repair it after I get back from my deployment.


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## A_USER_NAME (Apr 26, 2013)

So I got a hold of a glass company to cut me a new bottom sheet of glass. It should be done here in the next few days. It surprised me how cheap it was, for 3/8 inch glass custom cut it was 38$.

So I know I need to research, but are there any vital tips to replacing the tank bottom that I need to know? Thanks for your help, I've only got 5 days to get this done, including waiting for the glass to be cut!


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## lilscoots (Mar 13, 2012)

be sure to remove all the silicone from the old glass including the filets up the side corners (you'll be replacing the filet not the butt joint), using numerous razor blades and finally fine steel wool. Be sure you've removed every last bit. Then clean it with denatured alcohol or something similar to remove any grease or residue. In your case, flip the tank upside down, lay a bead of silicone (I use GE silicone I window and door) along the entire perimeter (bottom edges of the side/front pieces) and set the new bottom onto them. The goal is to not have air bubbles in any of the seams, to remove air bubbles you can put some silicone on your finger and push it into the joint to push the air out the other side of the joint. once you have all the seams with no air, tape the bottom to the sides with strips of tape, spaced all the way around to help hold the bottom to the sides while you have someone help you flip the tank over, at which point you'd run a new filet in all the corners and around the base perimeter. also a roll or two of paper towel is always helpful when working with silicone.


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## A_USER_NAME (Apr 26, 2013)

So I was almost done removing the last bits of concrete and glass, when the face of the tank broke. Oh well, I'm over this tank. I'll take all of the panels apart and fix it when I get back from my deployment.

Time to go to buy a tank.


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## A_USER_NAME (Apr 26, 2013)

So I was almost done cleaning the glass and go figure another panel cracked. So I went and bought a tank, a 38 gallon bowfront.


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## rgr4475 (Mar 19, 2008)

A_USER_NAME said:


> So I was almost done cleaning the glass and go figure another panel cracked. So I went and bought a tank, a 38 gallon bowfront.


That stinks, but at that point I would have done the same thing! Good luck with the new tank!


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