Resealing Tank(s)

[gooyferret]

You see the tank of your dreams and the person selling it tells you its sprung a leak. You buy it cheap and decide to fix the leak... Well lets get started.

What you will need:
1. Bottle or tube of 100% silicone, your able to pick these up either at your local HD, LFS, or your nearest Home Improvement Center.
2. Razor Blades (caution very sharp)
3. Bottle of Rubbing Alchohol and cotton swabs.

Ok you have every thing you need so lets get started.
First you will need to fill the tank so you know where the tank is leaking. Gradually fill the tank (outside so you dont get a mess inside) filling it slowly will help determine better where the exact location of the leak is.

Second empty the tank and leave to dry. Take a razor and slice down the middle of the silicone press firmly it will be fairly difficult to remove. Then take the razor along the edges firmly and peel the silicone away. It may flake or crumble. Remove all the silicone above and below the leak about 3 inches. Make sure you remove the old silicone as good as possible and try to remove as much from between the 2 panes of glass as you can.

Third you will have to clean the area that the new silicone will be applied. Either use a vaccum hose to suck chunks from the area or wipe extremely well. Next take the rubbing alcohol and dab the cotton balls and wipe the area generously. Use a dry towel to wipe after. Repeat this a few times then let the rubbing alcohol dry and evaporate.

Fourth apply the new silicone to the seam use a decent amount and dont be to stingy. The silicone will begin to become very sticky in about 2 minutes so you will need to be quick. Next use your finger and rub it along the silicone lightly. Rubbing your finger will help spread the silicone along both sides of the seam and give you a better look. When appling the silicone to the already exsisting silicone (the old that you didnt cut out) apply it over the top of the old and smooth it flush. This will ensure that you dont have a seam that would be weaker between the old and new silicone.

Now all you have to do is clean any excess silicone that may have got onto the glass or smoothing the seam a little. Just use a damp cloth or towel to do this. Now just leave the silicone to cure, it should say on the silicone bottle of the cure time. Usually around 24-48 hours.

This is what i have done for resealing tanks and hasnt failed me yet. HTH all of you! Good Luck.

[William]

A wet finger will help you smooth out the silicone easier.

..Won't it?

be less of a mess to.

[An t-iasg]

Good point, William...well, I don't know...I've never done this before! But I'm going to keep these instructions because my tank's silicone is stained from medicine, and someday I'll want to fix it. But...doesn't the silicone have to stay dry until it cures properly? So your fingers should be dry too??

[gooyferret]

I have heard both ways actually keep it dry to help it cure properly is what i think.

[justDIY]

water on top of the silicone won't affect it, however, water between the silicone and the glass it is supposed to be adhering to will effect the integrity of the joint.

you can also use 90% isopropyl alchohol instead of water, that way most of it quickly evaporates when you're done smoothing.

[peterp]

Neat, I got a tube of clear MARINA aquarium sealant, and it tells you in 4 languages not to put it in your eyes, how to open the tube, and what it will adhere to. No mention of the cure time

Assuming 24hour will do. Using it to glue tank divider guides into 15gal tank.

[vega]

Most sealant take few minutes to 'skin' and another 24 hours to cure.

[gooyferret]

I would recommend letting it sit for at least 24 hrs. no matter what the tube would say just to be on the safe side. DIY is this what you wanted for a sticky on resealing tanks? HTH

[HOLLIEO]

Okay, so what if you want to tear out ALL of the sealent and not just a portion?
What would be the best way to do this? Should I start with one side, cure, and then the next.. taking like 4 days? Any ideas???

[ArachnidAcolyte]

Do you have to cut out the old seal or could you just reseal over it??

[captainGregor]

Do you guys have an opinion on silicone? Can it be from HD or does it have to be "Aquarium Safe?" As an engineer my thoughts are - 100% silicone is silicone and that's it, no matter what marketing crap you put on the tube. Please share your thoughts.

[dean100]

Be very careful of sealants with fungacide or other additives as they can be very harmfull to your fish.

[captainGregor]

I just wanted to put my 2cents worth here guys. I have used GE Kitchen and Bath silicone from HD to create rockwork and caves in my new 55G tank. After doing a lot of research and reading Material Data Sheets I found that that silicone contains some (do not know which) chemical that is a fungicide (algaecide). According to many sources it is toxic to fish. Everyone recommends using GE Window and Door rubber sealant silicone as safe for tanks. Now I have to take apart all the rockwork, clean it up and do it again. I just do not want to take any chances. I read some conflicting stories where fish was dying like there is no tomorrow and other stories where people use mildew-resistant silicones for years with no problems, so go figure.

[Terry]

Over here in the UK there are a couple of sealants to use for aquariums, there are Dow Corning sealant and a parent company called Geocel, these products are 100% safe for aquarium use.
Any sealant that is used for outside use ie. fixing widows etc has chemicals added.

When it comes to repairing aquariums if it is just a reseal and you are not taking the aquarium apart i think that 24 hours is fine for the sealant to cure. If it is a rebuild then i would let it stand for at least 48 hours before putting any water back into it.

[xander]

I have a seam leak all the way down the corner. The top rim has cracked in that corner. What do you recommend for the rim? Will a slow cure epoxy resin do it or do I need to reinforce the whole rim. This is the second time this tank has sprung a leak. While I am at it shall I recaulk the whole tank at once? I was thinking of getting a new rim of wrapping something around it to secure it. I would rather just epoxy it.

[Sati]

I'm reading this and thinking if you have a leak you ought to re-seal the entire tank. I'm so paranoid about leaks (though I've never had one) that I'm wondering if we shouldn't re-seal all tanks every so often to be safe. That sounds like a big pain in the *** though :P I want acrylic!

[gooyferret]

How big is the tank xander? IF its like a 10 gallon or 20 i would just purchase another new tank. (cheaper than buying some good silicone to reseal). IF its a larger tank i wouldnt recommend resealing the entire tank since the factory seal is far more superior of a job. Is your stand and tank level, this could be a possible reason why your leaking since if its not level it would jar the tank and weaken the seals. HTH

[xander]

I think its a 30 gallon. 36" 12" 18" approximately. I haven't seen this shape of tank in local shops lately. I figure if I can fix it I will keep it. I want one about this size for feeder fish or a quarantine tank. No its not 100% level. I fear if I remove the bands on top and bottom to re-silicone the whole tank that I will have to replace those as well. Not sure where to get new whatever you call those things on the top and bottom of glass aquariums. I already siliconed the faulty corner and put JB weld on the cracked band. The silicone on the bottom looks healthy but the corners could use a little help. I don't want to pull up the bottom to fix the corners. Shall I just scrape off the old stuff without splitting the seam to get out the old stuff in the contact point? I was thinking of just getting off what I can without taking it all apart and then reapplying the silicone.

[Sati]

Originally Posted by xander

I think its a 30 gallon. 36" 12" 18" approximately.

That's a weird size. About 34 gallons...

[xander]

make that 36" long by 12 1/4" wide by 16 1/2" tall
I have another tank that is the same only 1/4" taller.
I measure from the outside. farthest level point to opposite side.