We had the same problem on some ground my dad just bought. We took some inch and a half square tube i think it was 11 ga. and put an upright about every 4 foot. Put a bolt in the very top rib through the tank and the square, and tack welded on the ribs all the way to the bottom. My dad is a great stick welder, I would just burn a hole in the tank. Anyway we welded a cross piece of inch and a quarter square on those all the way around the tank. I know it dosn't sound very heavy duty but square tube is strong. Bulls haven't bent it up. Only took a couple hours to do. They have to stick their head under the bar to get a drink, kind of like a bale feeder. I can try to take some pictures of it on Monday to put on here.