We have a 210 gallon tank. Tank is glass, heavy. The floor below the tank is supported by well framed closet in the room below in the basement, and is up against a load bearing wall. Its been there for 10 years, no distortion/stress. We are on our second tank over that time (first one was 180 gallons) but the wife was afraid it was going to be compromised. My music studio is in the room below, 20 guitars, drums and lots of electronics.... she thought it better to be safe than sorry so we replaced that tank with the 210 gallon one. Years ago she had a smaller one split causing a wee bit of a mess....
Tank is fresh water (brackish) with a variety of African Cichlids. Does require double the filter systems, aerators etc at that size. We have a pro come and make sure all is well every 4-6 weeks and my wife maintains it in between his visits. The fish are her thing. We have plenty of breeding going on in the tank producing cost effective new fish
. A sign of a healthy tank environment.
That size is a lot of weight. Water is 1750 lbs, tank is 350 lbs, plus rock, stand, filters etc... at least 2250lbs. But no issues....