Have you tried toys in his stall to occupy him so he might not dump his buckets? My APHA mare has a real oral fixation wiht stuff, when she was a foal we had a toy called a pacifer for her pen and it helped some, she still likes to play in the water tanks, but no longer dumps them. Here's a link to the toy:
http://www.horse.com/item/pas-a-fier/SLT200032/ Although, with metal stalls, you wouldn't be able to attach it to the wall, so perhaps something like a jolly ball or perhaps just an empty feed tub. My young stallion has a Jolly apple in his pen, no hanging, just on the ground and he chases that thing all over pen (doesn't like the jolly ball); here's the apple:
http://www.horse.com/item/jolly-apple/SLT203159/ Its rigid plastic rather than flexible rubber.
For my girls that paw their tubs and dump their feed, we took a "low pan" and added concrete to weigh it down. Here's the pan:
http://www.horse.com/item/fortiflex-low-pan-3-gallon-black/SLT901472/ We turned it over, filled the "lip" with concrete, let it set up, turned it over and walla, no more tipped over feed dish (I can barely move them, but, amazing they can still slide them around quite a bit). One girl is still using hers, the other now has a bucket attached to the wall.
For a water tub that maybe he'll leave alone, go to your local cattle supply place and see if you can buy an empty metal tub that supplement licks come in. Around here they carry Smartlic
http://www.smartlic.com/ (link is so you can see what the metal tubs look like, the 125# tub for horses is holds 15 gals, the 250# tub for cattle is like 30 gals), the other company I know of is Crystalyx. The metal tubs have a deposit for return, and many o fthe dealers will let you buy one for the deposit fee, which once he leaves you could then return for your deposit. [i'd see if you can get the Natural lick or horse lick tubs as they won't have contained anything harmful to horses; although they clean up pretty easy, so probably not a big deal. I've bought the horse tubs for my saddle horses in the past, and kept the tubs for mini feeders, they work great.]