Your just gonna need to be patient with the silicone. you need to fully empty the tank, remove the damaged areas of silicone, rub it with rubbing alcohol, then let it dry for a while, overnight is probably for the best, you don't want to rush this. The area needs to be completely dry because silicone will not stick to a wet surface, then after that the silicone needs to cure for at least 24 hours. I would wait 48 hours though because being patient with it will probably save you a lot of time and frustration.