After a terrible accident where the room heater was accidently set on HIGH instead of the thermostatted setting. I enter my colonly room to find it was about 100 degrees. Thank goodness my house didn't burn down. Unfortunately I lost all but 7 beetles. But had the luck of my pupae trays being unscathed, except for several mutated half-pupae-half-beeltes that developed from the heat. Unfortunately it lead me to my first bout with grain mites. Having watched some videos on how to manage this, thanks SCM, I didn't feel entirely helpless. Below was is my process. I'm 3 days into it and have noticed marked decreases in numbers.
It being winter I turned off the room heater completely. It now sits at around 60 degrees. I did this to control the mite's reproduction.
I used petroleum jelly to line the tops of all my bins to control the spread. I also wipe away any mites on the side walls twice a day below the jelly line.
I removed all food/moisture sources from the tray.
I set traps, 2 kinds. One, I used inverted yogurt cups with an apple on top. Every 12 hours or so I've been pulling them and washing off the mites in hot soapy water. Did this 3 times before switching to my 2nd trap. Two, being an organic gardener I have horticultural grade insecticidal soap which is something I haven't seen anyone use or talk about. It's OTC, you can get it anywhere. It kills soft bodied insects like aphids and mites but does not harm those that are shelled. I don't let it touch the substrate. Simply mix with water and pour into a jar, placing the jar in the middle of the bin. It's working like a charm. The mites climb up the jar and into the soap water.
I've noticed marked decrease in population. Maybe about 20% of what it was 3 days ago. I'll post an update.
Here are pics of the mites under my microscope and of the insecticidal soap trap set up.