Tank resealing

[stewmiester]

Hello everyone!! I recently purchased a large used tank. I knew the tank had a leak in it. I decided to reseal it. the tank is leaking in the bottom back seam. I've researched everything possible to make sure I done this right. Razor blades and alcohol, done everything exactly like I was supposed to. Filled it up a quarter of the way, held fine. Waited a week then filled it up halfway. A few days later all the way. Held water fine. Waited a month fully operational, pumps running and everything. About 3 months later I come home and the tank is completely empty. Removed everything from the tank and I looked at my back seam. It had split perfectly straight right down the middle. It was still hooked to the back panel and the bottom panel but looked like it was cut with a razor blade in the center of the silicone. So I guess my question is, is there a stronger silicone? Is there something else I could do to make it stronger. A larger bead maybe? I've looked everywhere and can't seem to find a solution. Any help or information would be greatly appreciated. Thanks in advance!!

[jonwright]

Sounds like to me the glass panes have totally separated. A bead on the inside wont help that from what I've read.

I'd logo at complete disassembly myself at least for those panels. I've read where folks will use fishing line in the silicone bead so that the glass doesn't squeeze out the silicone bead.

Your research may show you a different conclusion but that's sure what I'd be looking at

There are many recommendations for silicone. Rtv based seems to get the most nods.

[stewmiester]

Complete disassemble would be quite difficult. It's a 265 gallon tank, and nothing else is leaking. I'd honestly hate to tear it all apart to fix one leak I'm sure if end up with a few more. What exactly do you mean withy the fishing line??

[omrisiso]

Originally Posted by stewmiester

Complete disassemble would be quite difficult. It's a 265 gallon tank, and nothing else is leaking. I'd honestly hate to tear it all apart to fix one leak I'm sure if end up with a few more. What exactly do you mean withy the fishing line??

Let the tank dry thoroughly and then start working on it again.
Paste it so -
Thick silicon + 20 hours drying.
More thickly +20 hours drying.
Wait two days.
More thickly + 20 hours drying.
More thickly + 20 hours drying.
Wait a week, let it dry thoroughly.

Take a towel and put it under the tank.
Water fills up a quarter of the tank and wait three days.

If not leaked then you can proceed.
Another half fill the tank and wait three days.

If not leaked continue.
Fill it to the end (but to the end) and see if the fluid.
Give the tank a week or more.

[SuperDaveA]

I know your not going to like this, but I second the complete disassembly. The strength of the bond is not in the fillet itself. It's in the silicone between the panes. If you've got a penetrating leak between the panes, then your going to continue to have problems with leaking. I had the same problem on a smaller tank which I tried to just remove the fillet and re-silicone. Ended up leaking again. I just got rid of the tank and bought a new one (it was 30 gallons, so It wasn't a big deal).

You might be able to find a local tank shop or glass shop that would disassemble and refurbish the tank. Those guys have the right equipment to handle the material and size appropriately.

[stewmiester]

Omrisiso-- so your saying to apply silcone and wait to dry, then re apply in layers again? I didn't think that silicone would stick to silicone!?


Superdave-- I do have a lfs an hour away. He said $600+ and he could only garuntee it not to leak in his store. He said the biggest thing with me rescaling before was moving the tank because it was so heavy. So if I do have him fix it and it doesn't leak then the transport home I'm sure would cause it to leak and I would be out all that money. So I'm thinking my fix has to be on the stand which is difficult as well.

[SNAKEMANVET]

I fixed a 240 that had a broken bottom glass.I would remove the bottom glass and clean it really good.I used a drill with a wire wheel brush to remove any silicone residue.I bought a new piece for the bottom and used about 3 tubes of silicone.The tank did great for a year and a half until I broke it down to go smaller.

[omrisiso]

Invest, buy new and this.

[Mrramsey]

I'd just buy a new one. The tank leaked when you got it and you attempted to fix that. You have to consider the probability that the other seams are stressed and old as well and while not leaking their is a greater risk that they will in the future.

Replace the tank and have some piece of mind. Even the LFS guy said he would do it buy not guarantee it.

[uncleof6]

Originally Posted by stewmiester

Hello everyone!! I recently purchased a large used tank. I knew the tank had a leak in it. I decided to reseal it. the tank is leaking in the bottom back seam. I've researched everything possible to make sure I done this right. Razor blades and alcohol, done everything exactly like I was supposed to. Filled it up a quarter of the way, held fine. Waited a week then filled it up halfway. A few days later all the way. Held water fine. Waited a month fully operational, pumps running and everything. About 3 months later I come home and the tank is completely empty. Removed everything from the tank and I looked at my back seam. It had split perfectly straight right down the middle. It was still hooked to the back panel and the bottom panel but looked like it was cut with a razor blade in the center of the silicone. So I guess my question is, is there a stronger silicone? Is there something else I could do to make it stronger. A larger bead maybe? I've looked everywhere and can't seem to find a solution. Any help or information would be greatly appreciated. Thanks in advance!!

As others have already tried to put forth, there is only one way to fix this tank. That is to disassemble it and rebuild it. You cannot reseal it, you cannot patch it. (You found out the hard way, that you cannot patch/reseal it.)

There are two parts to an aquarium "seam:" the structural seam, and the inner seal. The inner seal protects the structural seam, while the structural seam is what holds the tank together.

For a tank to leak, the inner seal must be compromised, and the structural seam must be compromised. Once a tank leaks, redoing the inner seal is doing only "1/4" of the job. That is if the reasealing is done right, the tank will not hold together, and will eventually leak again, and possibly fail catastrophically. It does not matter what silicone you use, the tank will not "hold together."

To clean up some bad information:

You cannot apply new silicone to old used silicone. It simply will not stick; applying fresh silicone to cured silicone may hinder the curing process of the new silicone as well.

You cannot apply silicone in layers. The layers will separate due to air pockets between the layers, and it is just a complete waste of time.

Someone that offers to repair a tank, for $600, then will not warranty the repair, to put it bluntly, is just a rip-off artist, and I doubt there is any intent to repair the tank properly. If the tank is repaired properly, there is no reason NOT to warranty the tank for a few years anyway. With an abuse clause, "if the tank is abused, you get to pay for damage to the residence." Run from this guy, run fast and far...

Despite many tales of large tank diy repairs, it is very unlikely, having no experience in tank disassembly/reassembly, that you can successfully repair the tank, in your garage. The tank MUST be completely disassembled, and rebuilt. There are no shortcuts, no quick fixes, and darn little valid information on doing so, floating around on the internet. Note: mistakes in assembly technique, can often take a couple years to cause a catastrophic failure, so it will be quite a while before you know if "you did a good job." And, no...there is no "well if I can get a year..." it may fail the day after you fill it with water...

Hopefully, you learned a lesson here: never buy someone else's problem. Honestly, the guy should have paid you to haul away his garbage. As a builder, my advice is take it to a professional builder (not a glass shop) and have it done right (expensive) or use it for a reptile tank, and better luck buying a large tank next time...

[stewmiester]

Thank you for all your information and help. I have other tanks if this one doesn't work out. I got a good deal on this one and at the time I couldn't afford to buy one this size new at all. But I'm gonna keep trying there's no harm in that. If all else fails I'll just have to settle with my 180

[stewmiester]

Update: I scraped the silicone out and cleaned with alcohol. Let air dry. Used GE II silicone put a larger bead than before. Let it dry for 72 hours. Added 2 inches of water. Marked the level, waited 24 hours and held. Added 10 inches of water roughly 120 gallons now. Marked it and it held for 10 days. Last night I went ahead and topped it off. Another 18-20 inches marked it and it has held for 24 hours. Still gonna give it a few weeks before I add sand rock and salt.

[hllywd]

Potentially ~265 gallons of salt water on the floor, pumps burning up, livestock dead because of a Band-aided tank? I hope your insurance man isn't following this thread!

You already know the tank has a structural flaw that you did not repair. In fact you bought it that way! Further GE Silicone II is a consumer grade sealant that the last time I looked even stated not for aquarium use in the fine print... What part of this "bargain" tank makes sense whether it leaks today, next week, next month or in a year? It's catastrophic when it does, and a bad seal at the bottom of a is going to blow out when you least expect it. If you're not there to catch it when it unzips, you lose everything housed in the tank. Heck, depending on the setup, it could be a fire, or electrocution hazard. I don't see how that could ever be deemed an acceptable risk!

The only real fix as previously stated is to dismantle and clean the tank entirely, then rebuild it using professional grade adhesive type silicone, uncle can point you to the right stuff... Nobody is telling you to take the whole thing apart for the fun of it, simply providing the only safe solution. There is a reason the previous owner considered it unusable!

[stewmiester]

Thank you for your input. I understand there is only one way to properly do it. But sometimes the so called right way isn't an option. Myself like many others on here are not made of money or have the resources to do that. As for a disaster that is possible in any tank. Brand new off the shelf tanks have possible flaws. As you stated it's not a case of if but when. That applies to your tank as well. Nothing is guaranteed to last forever! If it does happen It's not a total loss. I have other tanks to rehouse my fish and coral, and I had the opportunity to have a wonderful tank until the day it fails, or I upgrade.

[hllywd]

Everyone's tolerance for pain is different. Mine doesn't allow for a rather high likelihood of several thousand dollars of losses, and damage, let alone the possibility of endangering my home and family. Good luck.

[stewmiester]

You're exactly right! I'm not looking at it as a tolerance for pain but rather positive outlook on a job well done. You have to have faith in your efforts. Thank again.

[uncleof6]

Originally Posted by stewmiester

You're exactly right! I'm not looking at it as a tolerance for pain but rather positive outlook on a job well done. You have to have faith in your efforts. Thank again.

Well, yes you do have to have faith in your efforts, a positive outlook on a job well done...

However, you did not put forth the effort required for a job well done.

1) You used a junk silicone.
2) You did not repair the structural seam, which when a tank leaks, is damaged.
3) The inner seal does not hold the tank together.
4) You have faith what folks tell you, just to tell you what you want to hear—with no experience at all, and don't have faith in 20 years of experience speaking.


This is what happens: Good luck

[shabreeson]

I do agree with what has already been mentioned. Tank needs to have inner and outer seal.

That said. I'm all for a little more positivity and a little more experimentation. The tank will most likely leak if all your variables are the same. And if it doesn't leak...you'll have to live with a constant nagging in the back of your mind. It could start leaking at any moment.

Taking the whole thing apart is the best option...
The second best option, in my opinion is:
1. Scrape the entire inside with a razor alllll over again.
2. Use steal wool (think you skipped this and I believe this is very very important) to remove any extra residue. If it doesn't remove it, it will make the caulk dirty so you can go back over with a razor blade.
3. Clean off steel wool with water.
4. Wearing gloves, Clean with osoptopyl alcohol.
5. Order 1/2" or 1" THICK glass by 3 inch wide strips to basically euro brace the ENTIRE inside of the bottom panel.
6. The caulking process has to be quick! And do it all at once
7. You don't want the euro bracing to be soaking in silicone. I'm sure you know, it cures from the outside in. You want the the caulk to encompass the entire 1/2" edge and only 1" of the 3" width. Don't caulk the inside of the 3" strips of glass to allow air in!
8. Let cure for 1 to two weeks. Then apply some caulk to the inside edge of the bracing. This doesn't add any structural support but it seals off the air pocket you would have.

It's a bit hard to explain this plan via text but it will esentally give you a second "structural seal"
This "bottom euro bracing" technique was used on my rimless tank.

[uncleof6]

Originally Posted by shabreeson

I do agree with what has already been mentioned. Tank needs to have inner and outer seal.

That said. I'm all for a little more positivity and a little more experimentation. The tank will most likely leak if all your variables are the same. And if it doesn't leak...you'll have to live with a constant nagging in the back of your mind. It could start leaking at any moment.

Taking the whole thing apart is the best option...
The second best option, in my opinion is:
1. Scrape the entire inside with a razor alllll over again.
2. Use steal wool (think you skipped this and I believe this is very very important) to remove any extra residue. If it doesn't remove it, it will make the caulk dirty so you can go back over with a razor blade.
3. Clean off steel wool with water.
4. Wearing gloves, Clean with osoptopyl alcohol.
5. Order 1/2" or 1" THICK glass by 3 inch wide strips to basically euro brace the ENTIRE inside of the bottom panel.
6. The caulking process has to be quick! And do it all at once
7. You don't want the euro bracing to be soaking in silicone. I'm sure you know, it cures from the outside in. You want the the caulk to encompass the entire 1/2" edge and only 1" of the 3" width. Don't caulk the inside of the 3" strips of glass to allow air in!
8. Let cure for 1 to two weeks. Then apply some caulk to the inside edge of the bracing. This doesn't add any structural support but it seals off the air pocket you would have.

It's a bit hard to explain this plan via text but it will esentally give you a second "structural seal"
This "bottom euro bracing" technique was used on my rimless tank.

Water will not touch silicone residue. Although water is the universal solvent, silicone is not water soluble (an organic-inorganic polymer, inorganic backbone with organic side groups) though water has other effects with silicone bonding. The best 'solvent' is MEK, followed by acetone. With water you will just be exercising your fingers, hands, arms and shoulders, and in the end you will simply be worn out. Vinegar (acetic acid) is not much better than water with cured silicone.

Final cleaing, just before application of silicone is with Isopropyl alcohol. This is to remove the greasy fingerprints...it won't touch the silicone residue either.

Perhaps there is a lack of positivity here, but that is due to 20 years of building tanks, and the accompanying experience, coupled with a knowledge of how poor and lacking 90% of the information available on the internet is. Experimentation is discouraged, becasue like it or not, there is a right way to go about this and a ton of wrong ways...

[shabreeson]

The water is just to clean off some of the little flakes of steel wool. When I used isopropyl with a paper towel, it seemed to clean off some of the silicone..."smear"? Don't know what you'd call it. But the steel wool seemed to just move it around? I'd guess it's microscopic silicone bits that aren't really bonded to glass anymore. It seemed to work pretty well, maybe it was more of a fine physical removal than a solvent? I'm sure you're right MEK or acetone would probably work better.

True the proper way is to do it all over, like you said. Honestly Stew doesn't seem like he'll go in that direction. I think my idea has a little merit. What do you think?

[uncleof6]

It is not all wrong at any rate But if the OP does not do it all the way the right way, he is the one who will be suffering the consequences, not any of us...to encourage short cuts, less than 'perfect,' less than minimum, however it is phrased, would be irresponsible. The tank needs to come apart, and be completely rebuilt, using proper techniques, materials and supplies. If unwilling to do so, put the tank in a dumpster and buy a new one.