I'd upgrade it. As blorkiemom stated, your welds are gonna be your weakest point. Followed closely by those feet... It only has to bend slightly (or sink the wrong way in that styro) before it comes off balance, and tilts. It won't have to tilt much before you have a big problem.
for a 37 gallon, if it were me (after all these are only opinions and you know what they say about opinions...) I'd mix up 20 gal
of fresh saltwater a few days in advance, then syphon off 50 or 60% of what is in there. If you estimate a remaining 18 gal
or so thats only 200lbs and 2 or 3 adults can lift it and walk it over to its new stand.
Also with half of the water gone, you shouldn't have to worry too much about sloshing, and water changes are always a good thing anyways..
stands with 4x4 vertical legs and braces made of 2x4s are suprisingly cheap/easy to make. You can cover them in finish grade plywood and make them look very nice.