Mites won’t go away

[Gilmore_LV]

Hi everyone, this is my first post here, I recently got a boa from a local supplier and everything was fine at first but a few days ago I noticed my guy was spending lots of time in his water dish and there were little black specks floating in the water. I did my research and learned they were mites, so yesterday I disposed of all the substrate and decorations in the tank and disinfected it thoroughly. I bought him a new hide and stuff and substrate. I even baked the substrate in the oven to kill anything that might have been hiding. He got two baths and everything was treated with protect a mite before going back in the tank. This morning I woke up and checked on the boa and the mites were back. I followed instructions very carefully but I guess I missed something. Any help would be awesome.