How much weight can a 75g tank hold on its bottom?

  • We are currently upgrading MFK. thanks! -neo
yep its all about weight distribution..

Right, as long as the rocks are flat, it's fine but it also works in reverse. If there is a point or high spot on the bottom of the rock, it'll concentrate the all the weight there. Placing "eggcrate" under the rocks is always a good idea.
 
I saw a video of a guy stacking large rocks in an empty ten gallon. (i think the link was from here)

Then he took down the stack (which was much higher than the rim of the tank) and stood on the bottom rock. In a filled tank, the relative weight of the rocks (or something like that) is a lot less.
 
I've got at least 200lbs of rock and another 100-150lbs of gravel in my 125, and I recently just removed 75-100lbs of rock from it. So all told at one point I had between 375-450lbs on the bottom of my tank without issue.
 
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