I am super close to just saying f*** it with this "fixing the tank" project. If i coated the bottom and about and inch up of the tank with pond armor, would that stop all leaks? The crack is on the bottom panel and i dont wanna go through the hassle of fixing the glass. Would it work or would the pond armor not stick to the glass???

I personally haven't had any experience with this, however, why don't you check their website out, I'm sure you will get some help there

www.pondarmor.com/

i had google what Penn had posted and that product is great. i wish we had that
here in my place. however, i can share some experience on how did i do it in one
of my project. using ordinary plumbing epoxy, i had done it in two occasion:
positive application and negative application. the first one works perfectly,
the latter had some problem as it ages.

filling the tank inside over the broken glass is the best option provided you
have good support underneath the broken plate. (positive application)

having a box filled with the pond armor underneath the broken plate will
also works fine but as tank come to ages, water seepage will happen.
(negative application)

just sharing my ideas.