I tried to supercharge my starter by putting a small piece of pineapple in it to see if it would pick up some more wild yeasts. I'm pretty sure the pineapple had bread yeast on it because now my starter is as active as commercial yeast and lost all of its sourness. I even tried putting yogurt kefir in to give the acid producing bacteria a foothold and slow down the yeast but no, the yeast continue to dominate.

Oh well, time to start over.

I generally have good luck with whole wheat + dark rye flour. Takes a week or two to get started.