Interesting this tank doesn't have trim? I didn't even notice that in the pictures. I had to go back and look at them again. Also interesting that this tank has been running fine with out the trim and now all of a sudden the tank needs trim? I just think that's odd? Is there a point like 5 years down the road or 10 years of running a tank fine without trim then the tank has to have trim or it will "blow out". I wonder if there's a thread about the age of tanks and trim requirements. Also same goes with the stand. Does the wood age significantly enough over the years where it wont support the weight after 10+ years? 5+ years? My 450 is on a particle board stand, it's gota be 10+ years old. That's not even real wood!
Dang this fish tank stuff is so confusing...............
its not odd if the tank was used as a reptile tank with no water as suggested.
its a huge tank, but my concern would be this:
I have been in the hobby for over 25 years and have had older style tanks with no trim, although they were not that big (90g, 65g etc).
the thing is, 90g tanks with no braces were made with 1/2" glass back in the early 90's.
my first thought was from the tank pics, it looks as though 1/2" glass was used, which would be okay if the tank was braced/eurobraced.
however, its not. back before they used braces, tanks that size would use 3/4" thick glass.
I would be weary of the tank as it stands. for a braceless tank, you always get some degree of bowing. tanks back then were designed with this in mind. if the silicone is older and has been allowed to dry out, that normal degree of bowing could cause leaks/or even a burst seam.
I would reseal the tank and add bracing for sure.
good luck with your huge tank! so envious! congrats!