# silicone releasing from aquarium - repair questions



## doctorb (Jul 28, 2008)

I asked this in a thread but here's the same question in it's own thread:
SO I'm not sure if this will do or if I should start a thread but here's my question along silicone lines:

I have a 75 gallon that's probably 15 years old. What's happening is that there's algae growing under the silicone in the corners. There's never algae in the tank between me using a sponge and the pleco, but it's in the corners, just beginning to separate the sealant from the glass. I'm afraid that it will cause a leak eventually.

Anyone ever experience this? I'm not sure what to do about it. I could cut a line because it hasn't made the corner yet and then add more silicone, but silicone won't stick to itself so I'm not sure if that'll help. I don't really trust myself to rebuild the whole tank, but I'm not sure I want to spend whatever a 75 gallon costs.

Suggestions?

The replies were:


Peppee said:


> That's something to start a new thread about. Are you sure it's not mold?





Deku said:


> i agree and i also agree that its mostlikely mold





onefish2fish said:


> well if you do decide to re-silicone the tank they make a black aquarium safe silicone, i just dont know if i would re-silicone a tank because of chances of leaks or worse, collapse.


The silicone (or whatever the factory sealant is) is lifting from the glass and there's green spots under it. Is mold worse than algae? And does knowing the difference affect what I should do? I know a glass guy and he suggested trimming as little as possible and adding silicone over the entire old bead, so the new stuff touches the glass on both sides of it.

That sounds reasonable, but I'm just not sure.


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## wake49 (Jul 2, 2008)

The only problem with that is that silicone does not stick to cured silicone. If mold is growing under your old silicone seal, it could continue to grow in that place unless you completely encapsulate it...


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