Smallblock;698121 wrote: Anyway what you want to stay away from is the kitchen and bath types have the antifungal/ mold n mildew ingrediants. Some silicones will say food safe or food quality. I have used the dap, black and the ge II black. I believe they both were window and door. They don't say safe for aquariums because they don't want lawsuits. They are safe. I can vouch for those 2.
Some of the aquarium ones have a differant curing agent in them. These are probably safer if you had to repair a tank or sump etc that has water in it or you cannot avoid letting it cure for a few days.
Robb the silicones are RTV Room temperature vulcanizing. I think the added ingrediants are the curing agents. The ingrediants that keep them soft untill exposed to oxegen. Theory.
Points, Stay away from bathroom and kitchen types. Make sure its 100 percent silicone. If you can get the DAP or GE II. Look on it and see if you can find one that says food safe or food quality. Make sure you don't get caulk because it has been proved to poisen the tank. Let it cure I'de say for at least 2 to 3 days to be safe. If you have the time a week.
Edit: If your still worried pm a guy named fishscales2. He builds tanks. I would bet he doesnt pay for the aquarium type because its pretty expensive.