You cant prevent spider mites from coming into your grow with a filter. You can get it from going to a different grow and then goin back into your room, from maybe going outside, or maybe getting clones from someone else that has mites on them. It happens when least expected. What i always do is i change out of my clothes or shower when i work on my room. I also have a set of work clothes that i wear when i do work. Even tho i have a small tent i dont have my friends over looking at it just in case they have mite on them. I had mites my first grow and it sucked so im very cautious now.
