100 Gallon Tank Needs To Be Resealed // Which Silicone Sealant?

PokeSephiroth

PokeSephiroth

Member
Got a wonderful 100 gallon tank from Lars On, and looks like it needs resealing. I've been reading around, and I've been finding that "GE Silicone 1 Sealant for Windows and Doors" has been widely used by many aquarists. Unfortunately, most of the articles I find, are of people fixing up tanks that are less than a 100 gallons. I've read horror stories of people using that same silicone sealant with tanks that are bigger than 100 gallons, and have had their tanks leak or even have the sealant fail on them due to the pressure that the water is giving off...

I've been hearing about the same things for "Aquarium Grade" silicon sealant, but the ones I find are rated for aquariums that are 30 gallons and below.

I can't seem to find a good aquarium sealant for a 100 gallon tank (Glass, btw)... I'm still going with GE Silicone 1, but still very hesitant...

Anyone have any suggestions as to what kind of silicone sealants you've used with tanks that are over 100 gallons? Or tips would be good, I s'pose... maybe I should leave a lot of the sealant on the seams? It doesn't have to look neat, since it'll be covered in gravel/sand, anyway, right?

I'm well aware that I have to remove all the old sealant before I add new sealant, etc etc... I'm just unsure about the quality of the sealant being able to hold a 100 gallon tank together. :confused:
 
lloyd378

lloyd378

Administrator
Staff member
Contributing Member Level III
We used aquarium grade silicon in college to seal a 150g. it kept that tank sealed up tight for the four years we had it. I went to CWU, and we bought the sealant and the local pet shop, and I can't remember the actual name. I will check with my friend to see if he remembers (but this is a small detail from over 10 years ago) good luck! You nailed it with the removal of ALL old sealant, and then just lay a nice thick bead all the way across. that's what we did.
 
PokeSephiroth

PokeSephiroth

Member
Thanks lloyd! I tried taking one strip of sealant off, and it was SURPRISINGLY easy, with a razor blade... the youtube videos that I've watched, made it look like it was going to be a real chore.

Either, the old sealant that was on the tank, was so old and brittle that, that's what caused the easiness of it all. I'm really glad I didn't test to see if the tank could hold water before doing anything to it. Hahahaha!!

Since it's a really old tank, it's got a lot of calcium deposits/lime scale/hard water, and what have you... should I clean up the tank first, with a vinegar wash, before I proceed to reseal the tank?

I'd definitely love to know what kind of silicon sealant it was you guys used! :)
 
Salzabar

Salzabar

Member
Dow Corning sells a black sealant for aquariums that IMO is the best at resealing old glass tanks. Problem is you have to literaly take apart your tank to get all the old sealant out and the tank has to be perfectly clean before you apply this stuff. Then it takes 7 to 14 days to cure before you can add water. Once done properly that tank won't leak a drop.
 
PokeSephiroth

PokeSephiroth

Member
Salzabar, yikes. Sounds like a little too much work for me to do alone. Does that also mean that I'd have to take off the panels completely, as in... completely disassemble the tank?

Because I noticed that when I took off one of the sealant strips, the glass panels didn't fall apart. lol!
 
Salzabar

Salzabar

Member
At least remove all silicone and clean it all up before resealing. When I had to reseal I was working with a 55 gallon so taking it apart was no big deal for me but 100 gallon? I would ask for help.
 
Salzabar

Salzabar

Member
Yuppers. All of it or you run the risk of another leak. Laws of physics and a bad silicone job don't mix.
 
PokeSephiroth

PokeSephiroth

Member
Gryphon: Gotcha on that. Thankfully, all the youtube videos I've seen, have mentioned about using isopropyl alcohol to clean up and residual silicone that the razors can't get.

Thanks for backing that up though! :)
 
A

Anonymous

Guest
Seems there are 2 steps to sealing a tank. The sealant between the panels and the bead outside the panels. The reading I've been doing on the subject requires a full panel removal. I too have been enquiring about the life of aquarium sealants. My 140 g is pretty old , I often wonder the life expectancy of silicone and glass tanks...

http://www.bestfish.com/tips/082798.html
 
PokeSephiroth

PokeSephiroth

Member
Madness, I've read that site during my researching phase, and I don't recall it saying what kind of sealant he uses... upon further observation, it looks like an older version of GE Silicone 1.

But the article, he repairs a 25 gallon tank, which I wouldn't be worried about, if my tank wasn't a 100 gallon tank. hehehe...

theChad, I have not seen this article before. Gonna give it a good read, but as you mentioned, if it comes to taking off a whole panel, that might not work well for me, since I have no help. Maybe I should just get it professionally done? Wonder how much that'll cost.
 
Salzabar

Salzabar

Member
Get some quotes and share them with us. I'm curious if 1) YOU CAN FIND SOMEONE TO DO IT and 2) HOW MUCH. Since the tank was free...right? Then I would try it myself. If you mess up then you're out the cost of the silicone and your time. The experience points you get from doing this project yourself will greatly improve what you can do in the future when it comes to tank restorations. Google search Dow Corning aquarium sealants or use that GE 1 stuff . Strip out the old sealant and lay out the glass panals on soft material (old carpet, towels, sheets, etc...) clean, clean clean all edges and corners of the panels...did I mention clean? Start with the bottom panel and silicone into the bottom trim ring using a spacer in place of the side glass panals. This way you have room to slot the side panels when you are ready to install them. I used tile spacers measured out the thickness of the side panels. Once the bottom panel is siliconed in firmly then go around with each side panel and silicone them in one at a time using a heavy tape to keep them joined at the corners and a square to make sure you have the 90 degree angles you need to make the box. I used a preform made out of 2x4's that I made prior to performing my tank reseal. Use what you want but just be mindful the silicone sets after a few minutes. Once the sides are up and SQUARE all you have to do is silicone the top ring and then wait at least 7 days before water testing. I would wait the full 14 days in a well ventilated area just to be sure its cured and ready for aquatic life.
 
PokeSephiroth

PokeSephiroth

Member
Thanks for the tips Salzabar :)

I'm very hesitant with taking the panels out myself, simply because it'd be my first time to do this, I'm sure I'm capable, just not confident. Hahaha!!

Madness, that brings more reassurance for me :)
 
A

Addicted2CAs

Member
I actually just did this on my 125 tall. It is 4'6" long, 30"h and 18" deep. The top had a frame but the bottom didnt. The first fill was a disaster as the back panel slid off the bottom panel due to the pressure. When this happened the pressure pushed sand along with the water out of the back seal between the two panels so now there is sand in between the two panels for about a 10" section, sketchy at best! Not wanting to remove panels and do it ALL over I went back to the drawing board and fabricated an angle iron frame that fit very snug. I then cut the old silicone out of the tank side and re-sealed it using a .5" radius gauge to get a nice transition between panels, the perks of being a machinist! I then put two massive beads of silicone along the two parts of the angle iron, creating a buffer that has a little bit of give when the glass pushes out, and slid it over the bottom of the tank. Just emptied it last night after a two week test and it is sealed up tight. There is no need to mess with the silicone in between the panels, unless of course it is completely degraded which is unlikely. Oh, and I used GE Silicone I, not II as it has a mold/mildew inhibitor that your fish won't like! Go to walmart, I believe I paid $4.30ish there for a 9.8oz tube as in the pic. At home depot they go for $6 something a tube.

I hope this all makes sense!

Heres the tank:


Angle Iron trim with silicone wedge in there:


And the silicone:
 
PokeSephiroth

PokeSephiroth

Member
Addicted2CAs, Oh WOW!! Thank you so much for that thorough explanation! That's more reassurance for me :) . . . one thing I noticed, is that my 100 Gallon tank doesn't have a brace in the middle of the top and bottom portions of the tank. I wonder if it would be more beneficial to add a brace, or I must just be thinking way too much about it, and just tackle the silicone resealing portion first? Hahaha... I get SO paranoid, after hearing/reading all the horror stories that some aquarists have gone through. Woo!!

There's definitely NO rush for me to use the tank, so allowing the silicone to cure is going to be an easy wait for me. I don't see myself using the tank for several months, because I also have to find out if the flooring of my house will support all that weight, once the 100g tank replaces the 55g. We're most likely going to find a way to reinforce the floor through the crawl space. It's a pretty old house (built in 1952) . . . so I'm not confident that houses built back then are sturdy enough to support the total weight of the 100g. . . . assuming that it will weight more than 1300lbs with everything in it.

So yeah, definitely need to check the flooring before anything else. Just figured that I'd worry more about the tank first than the flooring, since my partner knows more about that, than I do...so I'm leaving that portion of the challenge to him. LOL
 
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