Re: Something needs to change - looking for suggestions
sorry to hear about your bees. i haven't been at this very long but i'm starting to see that being able to keep bees successfully off treatments varies by location. i believe that quality of forage and presence of mite tolerant feral colonies may be the most important factors.
it could be that if you keep at it you might end up with mite tolerant bees. you'll have to make the call whether or not your commitment to not using chemicals is more important that suffering losses along the way.
i have been lucky so far in that my colonies are surviving and producing well off treatments. this is not by design as i didn't know anything about mites when i first started, and i did not deliberately set out to be treatment free. that i ended up not using treatments is from a combination of ignorance and/or laziness.
during my first winter with bees, i read everything i could get my hands on about beekeeping. in my opinion the best information out there on the subject is put out by randy oliver. what he has to say about using an integrated pest management approach makes a lot of sense, and may be a way for you to get to where you are trying to go without spending too much time and resources.
journaling the growth of a treatment free apiary started in 2010. 20+/- hives