Bioadvanced 3 in 1 application

[KatieM]

Hello there fellow orchid lovers. It's been awhile. Lots of blooms to be posted later on. Currently however not only are the dreaded mealybugs starting to show up but some spider mites as well. I've done the "natural" route for years, I've done a systemic (in granular form which I know mostly washes through). I've seen a few different comments recommending bioadvanced 3 in 1. It's time to bring out the big guns. My questions are:

1.) Do you water it in, spray it on, or both? I'd love to avoid spraying it on all my pretty blooms but if the mites get them they won't be pretty either way.

2.) Has anyone noticed any orchids that seem to be more sensitive to this product? I grow a large variety from phals and catts to ctstm, once, den, even a masde and mltps or 2, paphs and phrags. My vandas seem fine so I won't treat them unless I need to down the road.

3.) I know our little pests can build up immunity. Do you treat when you see them or preventatively and if preventatively how often?

Any other tips or advice are much appreciated. Again I am familiar with the natural remedies. Thanks in advance!