125 Gallon Placement/will This Even Work Help

[tetraodon_biocellatus]

Hello world,
 
     I am currently looking into the purchase of a 125 gallon aquarium, my main concern is weight. The location I am considering is on the second floor, adjacent to a load bearing wall. I live in an old home made of heart pine which is supposedly much stronger than other woods and no longer used in home construction due to the destruction of the south's old growth pines by loggers. I don't know how far apart the floor joists are but I can definitely check. I am planning on having medium-large amounts of rockwork in the tank as well so that needs to be factored in. 
 
   My other concern is a stand, I currently have a homemade table/desk in the spot that is just over 6ft long and currently has a 40 gallon breeder and a 20 long on it. It has 3 sets of 2x4's for legs and a very sturdy construction, however is it strong enough to hold a tank of that size, as of now its holding about 60 gallons of water, 50 pounds of sand, and about 70 pounds of rock.
 
Thank you, I can attach pictures if needed. I hope I included enough information to at least speculate if it would be possible. 
 
Cheers

 

[PlumbersMerchant]

I think the maximum load bear on joists is 1 tonne per m2 and that's if their 10inch by 2 ( standard British floor joists) not really sure when it comes to the usa. Just thought I'd offer that thought to ponder
Forgot to add, that's providing they are standard 16" centres or closer. Ideally you want to the joists to run away fro the wall you are placing the tanks against as it spreads the weight better

 

[squidneh]

http/www.cichlid-forum.com/articles/aquarium_weight.php
 
I had some concerns setting up my 75 gallon tank and did a lot of research to ease the stress.  The link above is one I cited when talking with a few others.  Give it a read.  We can give you advice, but ultimately you need to determine the structure of your home and come to an understanding of how much such a small surface area can bare comfortably, then figure out if the location you have chosen is safe.