Water alone is 1245 to 1660 lbs. What kind of tractor are you using? What kind of boom width you're looking for. That size will do about 6 acres with 30 gal / acre.
How hilly is your spot? What tractor are you using? Just spraying alone or are running a spreader too. I wouldn't run a 3pt tank that big with a tractor under 50hp. Keep in mind water slosh too for safe handling capacity. Tank splashes water on the side from a bump and can cause stability problems on side of hills. Might consider a towable if your tractor is smaller.