Resealing large tanks, crazy method

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uselessmidget

Jack Dempsey
MFK Member
Sep 28, 2008
98
3
38
Plainfield, Illinois
Today I got a 265 gallon tank for free. I noticed the wooden stand had alot of rotting wood on one corner. When I got there he was pulling the last of the water out with a rag and ringing it out into a bucket. He claimed that the tank had no leaks but I was doubtful. I have seen alot of threads about 265's leaking over time. I was planning on resealing just the fillet of silicone from the inside. I did alot of research via MFK and other sites and it seems the consensus is that large tanks require a full rip apart and resealing. I wanted to avoid this so badly I kept looking until I found this post on MFK about cutting the silicone seam out from the outside of the tank and jamming new silicone into the leaking area. Has anyone ever tried this? Link to OP: https://www.monsterfishkeepers.com/...leaks-big-and-small-and-repairing-them.33808/
Edit: I plan on just stripping and reapplying silicone to the inside first. So I am also looking for advice on which silicone to use, what method (how thick of a bead), any other advice for such a large tank, anyone in the Chicago land area available to help? I previously re-sealed 6x 33 Longs w/ dividers with GE 1 but I assume I need to use either SCS-2000 or RTV-108 for such a large step up. I would prefer a silicone in black but I dont mind using clear for more peace of mind.
 
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If the silicone between the glass is in good condition you can cut the old silicone out from the inside and reseal the inside.
I rebuilt a 220 with RTV-108 about ten years ago I have had no issues since.

Prep is key. Make sure that all the silicone residue is removed and the glass is perfectly clean.
 
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Usually the silicone between the glass doesnt need to be replaced unless its very very very old or was damaged somehow. You could put up some pics for us to see, but odds are you'll probably be fine with a simple strip and reseal.
 
Just want to bring it up again that that post talked about cutting the silicone out between the 2pcs of glass in the peoblem area while its still all together. Seems crazy to me, anyone ever tried it? Heres some photos of the suspected area.

20200203_155906.jpg

IMG_20200203_154834_01.jpg
 
Yea I'd definitely clean it out good and reseal. I have to reseal a 120 and was thinking about adding color to the mix.. maybe yellow?

Take some shots after you clean it and repost
 
uselessmidget said:
Just want to bring it up again that that post talked about cutting the silicone out between the 2pcs of glass in the peoblem area while its still all together. Seems crazy to me, anyone ever tried it? Heres some photos of the suspected area.

View attachment 1404140

View attachment 1404141
Click to expand...
So if I’m understanding. You want to remove all the inside bead and only a small section of silicone between a leaking area?
If that is correct I think you may have a problem removing the silicone between the glass good enough to make a proper bond.

I would recommend either completely disassemble the tank and rebuild with new silicone or only replace the inside sealing bead.
If the tank is not in danger of coming apart then the interior seam will seal the tank and prevent leaks without having to do all that.
 
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BIG-G said:
So if I’m understanding. You want to remove all the inside bead and only a small section of silicone between a leaking area?
If that is correct I think you may have a problem removing the silicone between the glass good enough to make a proper bond.

I would recommend either completely disassemble the tank and rebuild with new silicone or only replace the inside sealing bead.
If the tank is not in danger of coming apart then the interior seam will seal the tank and prevent leaks without having to do all that.
Click to expand...

So the 220 you did this way, was it an already leaking tank that you fixed by doing only the inside bead? From what I read if a large tank like this leaks the silicone must be replaced between the panels of glass otherwise it will leak again within a few days.
 
The 220 was a complete rebuild.

I have done several tanks where I just resealed the inside.
The largest was a 150 tall that was several years ago and it’s still up with no problems also.

A leaking tank that is otherwise in good condition ( meaning the silicone between the panels of glass because that’s what holds the tank together)
Then all it needs is an inside reseal.

If you look between the glass and the silicone is opaque and white looking not clear then that silicone has lost it’s holding power it is being sheared from the glass, you should do a rebuild.
Take the tank apart and rebuild with fresh silicone.
 
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There may only be a small spot that is the problem the rest of the tank may be in good shape and will stay together.
In these circumstances I would only reseal.

If I look at an end panel and the whole side looks to be turning loose I would rebuild that tank.

The 220 was coming apart hadn’t been used for water in years it was a reptile tank when I got it.
The 150 was a saltwater reef tank
I had that just started leaking. I think a crab had picked at the silicone.
 
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