I wouldn't use thrush buster. Thrush is caused by the hoof "rotting" due to excess moisture. I use a thrush powder that drys it up within a week and my horse basically have chronic thrush
Kopertox is what I use and it works really well for me. It is expensive though.
If u get sugar and bedadine and mix it until it's a paste and just paste it in the hoof then ductape it. It works great!! My barn uses this recipe for all the horses with thrush. If ur confused look up how to get rid of thrush with the sugardine recipe on google and it should pop up
Copper sulfate and white vinegar combined works wonders