I've done a few things.
Some salt can work wonders.
Being sure that it isn't exposed to the air as much as possible. (The yeasts mostly proliferate with oxygen; LABs mostly proliferate anaerobically.)
Adding a little Avi-Culture 2 off and on if needed/desired.
Cultured buttermilk can help.
One time I had a batch that I had been using for
almost 2 years and then all of a sudden, yeast overload. (I mean that I had kept the same batch going by feeding from it until it was almost used, then putting in more feed and water using what was left in the container as starter. I had never had a yeast over-load in all that time...it was easily fixed if I started to see kham yeast on the top, etc. Never had a problem keeping it in balance.)
It was just after I had purchased new grains (I make my own feed) and all of a sudden just couldn't get the yeasts under control. I chalk that up to more yeasts on that particular batch of grains that fall when they came in the bag.
What I did was finally started a new batch because nothing I did over a 6 or so week period of time brought it back into balance. I tried everything that would normally work but it just didn't respond.
I did feed the birds what I had as it wasn't so bad that it would hurt them; but
I started a new batch so that I wasn't continuing to proliferate the yeasts into what I was making new. I actually tried starting it new 3 different times and that particular batch of grains just kept causing the same problem. I finally had to get a different kind of container to make it in which made it totally anerobic at the start and that did the trick. (Like making sauerkraut or fermented pickles in the anaerobic jars.) But prior to that I hadn't started a new batch in almost 2 years.
Sometimes there is a slight difference in the feed coming from the mill or in the bags that just can't be fixed.
I've also heard from folks that ferment pellets or crumbles that there are certain brands that just won't ferment well. I heard the same brand mentioned more than once, and when they changed to a different brand, they had no problems. So if you start having issues, it may just be some of those things that need some tweaking
