Weight of rocks in tank? limit?

I have a 105 gallon tank - there are lots of rocks in it - holy rock, coral,
etc. - no gravel - the tank has developed a slow leak somewhere on one of
the bottom side seams - I'm removing the rocks and draining the tank - the
retailer has come out and looked at he tank (and the water on the floor) and
confirms that the tank will be replaced by the manufacturer - but the
retailer has made comments about the amount of rocks in the tank - like it's
too much weight - realistically, what kind of limits are there on how many
rocks (how much weigh) I can put in the tank? Any suggestions? Thanks!