How obvious are mites?

[DLLNP]

Hey everyone,
I'm wondering if it's obvious when you have a mite infestation?
I recently found 4-5 very small red bugs (I didn't count their legs, so I'm not sure if they are arachnoids...I should have counted..). I have looked everywhere for more evidence of mites inside the enclosure, on the animals, etc... With no luck. I also have observed no strange behaviour such as extended soaking or any soaking at all. It is possible that I have had some of my "clean up crew" from my natural vivs make their way into the snake tub (which has happened before).

Would I be able to tell very easily if I have a more problem?
I'm going to soak one of my boa's for a while to see if anything comes off. If nothing comes off, can i be confident that I don't have mites?

Thanks!