Drill a stop into the floor.
Not pretty, but 1,000x better that a broken tank if the wind gets a hold of the door.
Thanks for the idea. I currently have one that is on the hinge that can be adjusted, but it does feel a little flimsy. The type of stop you have there *might* work, I won't know for sure until I get it in there. It depends on how far back I decide to keep the tank. The only problem is I would be drilling into concrete, I also may end up blocking the tank doors. But I like your idea, I'll investigate alternative but similar options.
Fortunately that is a door to our garage, so while it is very frequently used, it is not much of a wind risk.