Sorry that I didn't see this thread yesterday, but I hope that you didn't buy that silicone that you were planning to buy. I too was looking at buying some sealer about a week and a half ago. I was at a local hardware store and I was looking at the GE stuff. I called the 800 number on the back of the tubes and talked to the people there. They said do NOT use any of their products in an aquarium as even after they are cured, they leech harmful chemicals into the water. I asked if they had any suggestions, and they said that DAP makes only one product that is safe and it's specifically for aquarium use. The hardware store that I was at did not have it, but went I went to town the next day, I found that Wal-Mart carries a "Lok-Tite" product that is aquarium safe and I purchased the only tube that they had left. I went to the hardware store not far away, and they actually carried the DAP product that GE recommended, and I bought both tubes that they had. I wish that they made an aquarium sealer that was "Easily" available in a large, caulking gun sized tube. If you have bought the GE sealer and haven't used it yet, please call the 800 number on the back of the product and they too will tell you not to use it.