How to Reseal an Aquarium | Resealing Our Fish Tank ---------------------------------------------------------------------------------------------------------- Special thanks to Kevin at N.O.A.H. Northern Ontario Aquarium Hobby https://www.youtube.com/channel/UC3D384hKLvQtSxoRWNKoN2w Today Mike and Kevin reseal our 75 gallon aquarium before it becomes an issue. The silicone on the tank was bubbling and water was getting between the glass and silicone. The fish tank would have eventually failed and started to leak or let go and made a big water mess. To start the process of resealing our fish tank Mike removed the old silicone first. A few tools that make this job easier are, scrapers of assorted sized, calking puller and some razor blades. Start by scraping silicone from each side of a seam. Once it starts to lift either use your calking puller or scrapper to remove silicone. Be mindful of adhesive, do not dig out seams as you may damage the adhesive. last step after most of silicone is gone would be to use Acetone to remove remaining traces of silicone from seems. Also note that Acetone will eat adhesive so do not apply to cracks. After your tank is clean you want to start taping your safe area with painters tape. You want to leave a 1/4 inch on each side of seam. Apply silicone in all seams and either use finger or calking spreader to spread to appropriate thickness. The last step in this process is to remove tape as soon as you are done spreading the silicone. It takes about 20 to 25 minutes before the silicone starts to harden up so these last steps have to be done promptly. Allow 24-48 hours for the silicone to cure. If you still smell a strong odor the silicone is not yet set. Allow additional time to dry if needed, until no odor of silicone remains. The last step is to fill the tank. We recommend slowly filling it over a period of 24 hours or more to be on the safe side. If at any point you see large stress fractures in the silicone it may be necessary to restart the resealing process. It usually means it did not adhere well enough, which can be caused by not cleaning the area enough prior.