for weight make sure you add the tank empty weight. 3/4 glass is around 10lbs per sqft and 5/8 is around 8. Add your sand and rock weight also into the figure.
Mine at 220.. Dry weight around 400 lbs, 200 lbs rock and 400 lbs sand, and around 1500 lbs water. All sitting in a 15 sqft foot...