Got a used 125 gal and I'm not sure if it's gonna leak or not when I fill it. Say it does leak, what is the procedure to re-silicone a tank? I assume it involves getting all the old silicone out and redoing the whole thing.

Is there maybe a tek on this? Thanks!

From what I have read (I had a cracked tank at one point, which I replaced, and was reading about it at one point) and you need to remove the panel where the water is leaking and then reapply the silicone.

Make sure to use aquarium safe silicone otherwise you will kill your fish.

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I strongly suggest you do a fill test like in your garage or somewhere its leaking won't cause any damage. If it holds water for a few days you will be good to go. If not find someone with a large snake to take it off your hands. Seriously, if it's a leaker you don't want it even repaired in your house.

I did a complete 55 gal by myself. It wasn't too bad, but for your 125 gal I would recommend a second person. And you do need a strong flat surface. I used my pool table. Remove all the old silicon and clean the glass with alcohol. Make sure you go a good job of cleaning and make sure you don't touch the glass where the new silicon will be applied. Use wide masking tape on the inside corners and taper the silicon down to it for a nice look. I had some straps ready to hold the tank together while the silicon cured but the silicon itself was enough to do the job. If you do use something like straps make sure you use Saran wrap under the straps so you don't glue them to the tank. I waited until the silicon had cured before I replaced the trim.

How old is your tank? My 55 gal was over 30 years old and the silicon had failed. I could rub it off in little pieces with my fingers. What I'm getting at is, you might want to do the whole tank and not just the one side.

DLH

All of the old silicon has to be removed where you are putting the new silicon---new silicon will not adhere to old silicon. I replaced a whole side panel on a 150 and it is going thru a leak test now so far so good

I think I used one of those plastic pot scrubbers to remove that last little bit of silicon that the razor blade missed.

DLH

Thanks for all the help!

I've read a couple teks on doing this now and feel like I can get through it fairly well. The one question I have left is about striping the silicone from the top. Every tek I've read talks about stripping out the bottom silicone and the inside corners, but not the top. Since new silicone doesn't seal to old silicone there would always be some leak potential at the top corners where the new and old silicones meet.

So, question is...When stripping out the old silicone is it common practice to cut out just the bottom and the sides, but leave the top in tact?

Thanks

PS Since GE Silicone I and II are now both 86-ed, where do I go for caulk gun sized tubes of aquarium safe silicone. Fosters and Smith maybe?

"So, question is...When stripping out the old silicone is it common practice to cut out just the bottom and the sides, but leave the top in tact?"


Could you explain what you mean a little better. Are you talking about the trim?

DLH

Thanks Don. Probably could've explained my question a little better.

When removing silicone, what I'm calling the bottom would be the rectangle you see when you look straight down into the tank where the bottom piece of glass meets the 4 vertical panes of glass. The sides are the four vertical articulations (or corners) where the sides of the tank meet. These are the seams that have to look neat because they aren't covered by tank framework.

Now the 'top' part my original question refers to the 'rectangle' of silicone that secures the top frame to the top edges of the 4 vertical panes of glass. This is the silicone at the top of the tank that is also hidden by the plastic framework.

Thanks again for your time on this one.