Bottom repair 66 gal

[Quagmire]

Just keep scraping,the film will slowly come off.You dont have to get it totaly clean,the new silicone will still seal if you get most off.I dont know if you have a top brace of any kind,but if not,then becareful to keep the tank as stable as possible.If the corners move too far off 90 deg.it may weaken the seal and cause a leak.