Wow, that's good to know. I've been using the GE Silicone I Doors & Windows for years in my sumps. I don't think I've had any issues...

Usually, unless the silicone is re-packaged like All Glass stuff, etc., the packaging will say not for aquarium use. Water will break down silicone over time (technically) so it's totally a liability thing.

I got it for pretty cheap at Calgary Fasteners.

Yup, $6 a tube at Calgary Fasteners and they had over 100 on hand. Thx all.

The old packaging for GE Silicone I had no mention of aquariums on it. Go way back , and it did say for aquariums; but their bulk customers complained people wouldn't buy their repackaged "aquarium" silicone when they could buy the GE tubes cheaper ..
GE took the "for aquariums" off the Silicone I for Doors and Windows, but does not say not for aquariums. I have not seen their new packaging for the Doors and Windows, but the Silicone I for kitchen and Bath does have the "not for" warning on it .
It boils down to read the fine print on the tube .
If it says "not for aquariums" , don't use it .. If it is still like the old Doors and Windows Silicone I and makes no mention of aquariums, it should be safe.

Why bother thinking about it? GE SCS 1200 series and no worries about anything. BTW, the SCS says clearly - Not for use on fireplaces, stove pipes, or below water. Like I mentioned before, water will slowly degrade silicone. If you looks at the corner bead on an old tank you can see the slow degrading. The actual seam is protected by the corner bead. Technically, the structural seam never gets wet.

On smaller high end tanks (like ADA) where there is no corner bead the tanks will often begin to fail after 3-5 years as the silicone weakens and starts to pull. They usually split from the top down and the slight bowing keeps working the seam apart.

It's always been about availability without the LFS pricing. Problem solved now for me at least. :)

http://img.tapatalk.com/464b85f3-b4eb-6969.jpg

I can for sure tell you the SCS 1200 is for sure the way to go and nothing else. Believe me I know. I would say that all the tanks I have are done in it. Don't cheap out on the silicone you will regret it later.

Is the SCS 1200 a GE product ?? (can't tell from the pics).

If not, who makes it ?

Yes it is a GE product but without any mold inhibitors, it is used for construction.

That's the good stuff madmak lol