stand doesn't look very sturdy to me. i would be afaid of it collapsing or the wheels breaking off with the weight of 2 tanks on it.
37 gal tank x 8lbs = 296lbs
30 gal tank say with 20 gal water in it 20 x 8lbs = 160lbs
296 + 160 = 456lbs
this doesn't include weight of tanks, pumps, skimmer, plumbing, etc.