I probably have one of the oldest/larger tanks on this forum.. have a 135 gallon 6 foot 40 year old tank (rounding it to 40 its almost 38 years old) in my bedroom built in 1982. It has 1/2 thick glass, no center braces like modern 125s have because the glass is thicker, they made tanks way way way better back then. I re-sealed it when i bought it 2 years ago, and its been running fine. The seals between the glass panes are really good, no air bubbles or seperation so i didnt bother with them. The only thing is one of the large 6 foot panes of glass bows without water in the tank.. Its from 36 years of being filled its perm warped the glass a little. Filled it bows about 1/2 an inch total.. Doesnt concern me in the slightest.
If the tank has plastic trim all you need to do is make sure all 4 corners are being supported and its level so it isnt twisting by being low on one corner and high on another and thats it. You dont need support in the middle outer parts of the tank all thats important are the corners.. Also being 100% level isnt needed for glass. Meaning if its a rectangle tank for example.. if the entire left side of the tank is down due to a house thats settled and leaning it isnt going to do jack to the tank. BUT if say the front left leg is lower and the other 3 are higher then you have a problem itll create twisting.. But one whole side being unlevel causing the water line on the trim to be higher on the left side of the tank and causing leaks is a myth on a trimmed tank, and i don't wanna hear otherwise from you guys it is completetly untrue. You only need to support the 4 corners, to make sure each corner is level with the direct other corner so it doesn't twist left to right. The reason Solitudes tank blew a seal with a uneven stand was his stand was probably twisting the tank.. That can also cause the glass to crack
To make it short.. leaning to the left or right wont do anything, but twisting down and up on seperate corners will
So yea i wouldnt worry about older tanks. I have a 15 year old 92g corner 1/4 cylinder bowfront tank, and a 25 year old 30g rectangle 3 foot long tank. No issues at all. In fact i would rather have my 40 year old 135 then a brand new 125/135, If you offered me a 200g tank brand new to trade for my 135... Id keep my 135.. New tanks use the bare minimum thicknessfor glass and acrylic and they cheap out on the amount of silicone to seal them.. screw that Id probably re-seal that brand new 200g tank then risk it leaking in 1-5 years. Have you see how pitiful the silicone seals are on all these new tanks ? I was in petsmart the other day and i was looking at the seals on the 150-90g-65g ect tanks.. Wow they are paper thin seals inside.. and outside the seals between the panes of glass are way too thick.. Silicone is stronger when its thinner so when you glue two peices of glass together you want thinner silicone not thick like these tanks had.. Inside where it holds water a good rule of thumb is to have silicone as thick as the glass itself. I would not want the silicone so thin i couldnt even feel the bump with my finger when rubbing it.. This is why alot of newer tanks leak after only a few years. Those brand new square shaped 150s thats petsmart sells.. read the reviews.. they leak after a year or less.. Thats because the silicone is WAYYYY too thin inside, and too thick on the panes of glass so it seperates.
I had a "newer" regular 55g tank. was only 5-6 years old and the silicone was so thin when they made it that it was already falling apart so i sold it.
The only thing you should be worried about are the seals.. re-seal them and youre done
My 60g cube was 22 years old when I upgraded to a 120. My 150 was 25 or so when I sold it. I've got a old 120 that I got used in 1988. It had been the feeder goldfish tank at a LFS for at least 15 years before that, so ~ 45 years and counting. Never resealed a one of them. All of them got moved many times over the years.
IMHO, it is as much the stand they sit on as much as it is the construction of the tank itself. If it is off level (even a little bit) it will add stress to the tank and probably lessen it's life expectancy.
You mean 35 years not 45? But even 35 is wrong. 2019-1988 is 31 years.. your math is off by about 14 years LOLLL
