I can hardly contain myself But, a friend has a 75 gal they are not using & they know my O lives in a 55. Ideally he would be happier in a bigger tank. I need to know how heavy it will be. we have a 6 board header under the house with cement block bases with jacks about every 10'. not sure if this is standard for floor support. ? how long is this tank? I don't know if a stand comes with.

could weight around 288 kilograms of water plus the
weight of the tank and stand.....roughly 320 kg.

so 650lbs approx plus the weight of gravel, rock extra. is that about right?

minimal changes on weight with rocks and gravel since you
will have water displacement for them. more or less you will
have almost same weight unless you fill the tank halfway

ok I was never good with conversions but give me a word to spell i already know I will need 2 canister filters for pristine water I will have to plan this out if I want it to be perfect. thanks

ha ha ha, we can work together... i am good in logic and
math but poor in gramar...

no kidding aside, that is common notion that rocks and gravel
are heavier. but when you put them in water, the water being
displace has the weight that should be deducted to the actual
weight of the rock and gravel in the tank.

gotta just out of curiosity are all 75 gal the same width and length?

nope, they could be of different footprints
and height.

a 75 gallon tank can come in a variety of sizes. but i think the standard i size 48x18x20.

that means the tank stand that my step dad made that's 48x12, has an open back (emerg build) can be turned around extended to fit the depth of the 75 and I can have him put access doors on the front and open some holes in the back for cords...i think that might work Mate! thanks

yes you can but there must be hard support at the
bottom coz the 6 inches cantilever (protruding) glass
could break at that point due to the weight of loads.

make sure to sit the tank on a solid surface like 3/4 inch plywood and foam to prevent bending the aquarium.