Mites!!!! OMG we have mites!!!

[GyGbeetle]

Very frustrated, because we STILL have mites! We finished our fifth Nix treatment of ALL of our tanks this past Sunday, and today, we found a SINGLE mature mite in the same tank we discovered mites in over a month ago. Just one. That's all we're finding, is a single mature mite every 2-3 weeks, in the same tank. All the tanks are being treated, none of the other tanks have had any mites, so where the heck is this single mite coming from?

We've soaked the snakes, nothing comes off ANY of them. We are now treating the tank we found the single mite in as I type this, but I'm getting frustrated. Shouldn't they be completely gone by now? I think maybe I should start the PAM tank method back up, with Nix treatment on the snakes, for another month. But that's soooooo much work, and I want to buy a new snake. Even in quarantine, I don't want to bring in another animal into this.

What gives? I'd understand it more if we found mites on one of the snakes, or found a bunch of mites. But it's literally a SINGLE mite, every 2-3 weeks. This is the third spotting in the last 5 weeks.

Please, someone help explain this to me, or what we're doing wrong.