Yes, just clean the area well and wait 48 hours for it to cure completly before it's exposed to aquarium water.

I'm not sure it has a maximum size other than the fact that one tube will only cover a limited amount of glass surface. It should certainly be fine for a 55 gallon aquarium. Hopefully you are aware that you need to strip all the old silicone sealant out and reinstall the piece of glass. You can't just fill an existing joint, spread it with your finger, and expect it not to leak.

Glass cage? Absolutely. Just be sure to let it cure at least a day before the hamster can get to the glue.

The tube says wait at least 48 hours before filling the aquarium with water.

I have used silicon like this before. Every leak is different. What you will probably find is the leak on the inside will flow under the silicon and come out somewhere else on the outside. You must figure out where the leak starts and clean out the old stuff to fix it. Or clean the whole edge of where the leak is and re apply to that whole edge on the inside of the tank.

Hi BekBek, We would not recommend using this Silicone Aquarium Sealant for that purpose. Thanks

Hi Sherryl, We sent you an email asking for more information on this query. Thanks,

Yes silicone is fish friendly.

Nope that won't work because eventually the pressure of the water will push the whole right back open so you need to drain your tank out completely dry it cut that whole side of the silicone out and then resell it make sure and let it dry for at least 2 days before adding any more water and check your water parameters