Alright you are all going to think I am nuts but just to change the subject briefly from vomit (because we all love vomit stories, I know) I have to share that my birds have WORMS! Now this doesn't sound like a 'yey' moment until you realize that I now have confirmation that my bird died from something very common and treatable and while I am not happy to think about how gross that is, I am happy to know it is something I can deal with easily. My son found worms in the feces to confirm this. Phew. So, I am guessing it is possible that the cider water and de in the food is helping but in the mean time I am going to try all of these things below, just not all at once:
soapy water drinks
bleach water drinks (yes, got this from a vet)
Safeguard from TCS
eating pumpkin (save that for the fall and will give the dog some too)
continuing to use DE in the food
cider vinegar for maintenance
Now, what do I do about the soil??? I don't want these buggers in there forever. Treating everyone and I made sure to tell anyone who bought from me. Just so I don't feel like a pariah, I read that this is very common and birds should be wormed at least once a year. Well, now I know and will. I say again, "phew." Hope this helps someone else.
I was kinda horrified when I found out mine had worms last year until someone very nice pointed out that all animals that scratch and peck in dirt will more than likely pick up worms at some point in their life. They'll most likely keep picking them up. That's why I worm mine each fall.
I do Wazine in the water (kills some of the load) then 10 days later I follow with an oral wormer, then repeat it again in 10-14 days. I usually do it each fall or if/when I see worms in the poo. Worms in the poo are a sign that they're pretty wormed up so you want to treat it asap.
Good luck!