Have a 100+ y/o cement pond, kidney shaped, appox 700 gal, 2.5 feet deep at the deepest. Recently decided to get it going again. Had a crack re-cemented, fiberglass patch and Pond Guard application to entire pond this past Saturday. The next evening, Sunday, (1.5days after Pond Guard application, 24 hour cure recommended) filled with tap water, dechlorinated, etc, tested water, everything perfect. Added tadpoles and 1 goldfish. Watched for 2 hours, everything good. Added rest of fish (5 goldfish, 5 mosquito fish). Watched for 3 hours, everyone looked and acted great. Woke up next morning, Monday, to everything dead but one goldfish gasping at top. Checked water again, all levels were good, Ammonia was .25 but after a mass genocide I figured might be par for the course. Baffled. Found out later that my husband put a small amount of GE Silicone II kitchen/bath (with mold inhibitor) on a few spots where he thought the Pond Armour was a little thin just an hour or so before we filled the pond. Perhaps 2 tablespoons worth, max. I am figuring this was the culprit. My question - pond was drained yesterday, Tuesday, and rinsed multiple times. With a longer cure will this be ok or will it forever kill our fish? Scraping out will be a mess and might pull off Pond Armour as well. Can something be put over the top of it? Sorry for the novel but wanted to have background incase anyone thinks it might be something other than silicone. Any recommendations would be GREATLY appreciated!