One of my horses has a tendency to develop seedy toe. In my experience, soaking alone won’t cure it. What worked for my horse was for the farrier to first resect the hoof far enough to remove the infection, then soak with Clean Trax (or generic oxine). We also shortened his trim cycle, so the hoof doesn’t start to crack and allow infection back in. And if I see any signs of a crack developing I treat with B Gone until the farrier can trim it out.
I don’t know if you’re familiar with hoof resection, but if the white line disease isn’t too far advanced it’s no big deal. My horse was barefoot after his resection and I rode him in hoof boots. He was totally sound the whole time and the hoof grew out good as new in a few months. More extensive resections can be stabilized with shoeing. The key to controlling white line disease is to treat it early and aggressively.