Iron stand with no braces in the middle... should I be afraid of hardscaping?

[splintercat]

I have a stand that is similar to this. Except it is 30in x 12in and holds my 29 gallon tank.
I went to the beach today and found some amazing rocks. I cleaned them, did the vinegar check, etc., but now I am questioning whether I should be afraid of the bottom of my tank falling through or something with the added weight... I'm sure they'd be heavier than the water they will displace.
Does anyone have any experience using stands like this & know if I should be worried?

 

[ezy33]

IMO if your tank has a frame you should have no problems. If not I would put plywood under the tank.