I have a 30amp 240 breaker going to a 240v water pump. I want to protect each leg with a GFI
In short, no. Each leg of a 240v circuit is is 180° out of phase and they share a common neutral. If both legs are hot, it will trip a 1 pole GFCI because the opposite phases cancel each other out on the neutral. You would need a 2 pole GFCI, which trips when there is a potential difference between the 2 hot legs instead of a single hot and neutral.