I believe there are lots of different thrush pathogens out there. I've found that iodine (providine) worked well for me one year but not the next. Bleach worked well up to a point then I had to switch to coppertox (thrush-XX is same thing but $10 cheaper). With thrush, everything always, 2x day. I tried Pete's goo several times but it never worked here for me.
Right now, the thrush-XX is what's working here and it's also melting and very muddy, yucky manure insulating snow piles wet wet wet paddock. I pick out, brush the hoof with a stiff brush getting everything I can out of the way of the thrush and pour. The coppertox/thrush-xx is moisture resistant.
Whatever you try, if it's not working after 2 weeks, switch to something else.