I used the GE 100% silicone sealant to create baffles in the sump. It says UV resistant but not mildew resistant. It is the little red tube that was in Lowes right next the acrylic/glass cutting center. When I called GE, they said, none of their products are safe for aquarium and that I should take it all out. I thought 100% silicone is safe to use. Do I need to get it all off and go with the one that has the aquarium safe label on it?