Is it OK to put a fish safe silicone over a silicone that's not really safe for fish? I made a shotty aquarium out of a 30(i think) gallon bucket and cut a square hole in the side with a piece of acrylic I molded to fit. I have siliconed it in place and it is water tight but the silicone is colored and has some anti-mildew additives so I need to put aquarium silicone over it to make it safe.