Hi dittmerj, and welcome!
First, according to the build your own tank guidelines at garf.org, your tank is:
Material = Glass
Tank Height = 36"
Tank Width = 36"
Tank Length = 80 "
Glass Thickness = 1/2"
Approximate Gallons = 449!!!
That's a really big tank!
I resealed my 125 gallon, and it wasn't that bad. There's a sticky post in the DIY
section, and I compiled all of that information into an article. My only concern is that that's an awfully big tank, so make sure you've got great silicone!
It is a glass tank, right? If it's acrylic, disregard anything I say.
Anybody out there an expert on silicone in VERY large tanks? I'd be curious to hear an answer on this one as well.
Good luck on your resealing! It should be a snap to do it yourself, just a little time consuming.