Hybrid starter in long term

Toast

I commonly see people mixing their SD starter with CY and I am wondering if it is possible to make sustainable hybrid starter. I was making a loaf today and while preparing the levain I took one spoon from my CY poolish, one spoon from SD starter, then fed the mixture. What happens if I keep this feeding in long term?

- Since common yeast grows faster would CY population dominate the starter in long term?

- Or SD starter would decrease the Ph thus eliminate CY bacterias in long term?

- Or they would reach a balanced population like %33 CY %66SD, and keep on like that?

I hesitate to overstate this but ummm No. CY should never be used in wild starters. You will not get a hybrid starter. 

From what I've read, commercial yeast cannot survive in a starter.  If you wanted it there, you'd have to keep adding it.  I'd think that its presence would inhibit the native organisms that make a starter what it is from reaching full strength.  Overall, it strikes me as a costly and counter-productive strategy.  

Commercial yeast will probably serve you better if it's added to the dough itself.  I've often run across recipes like that.  I've never tried it.

Is there any experiment about that which checks bactery levels after some time?

General consensus is the acidity of a starter is outside the optimal ranger which is conducive to commercial yeast growth and reproduction - there has been testing on this. Best to use cy in the dough not in the starter - which I do often. I also feed my starter with some of the dough I just made (along with normal feedings, and a little corn meal and oatmeal that I happen to spill on the counter here and there) and never had a problem. The bugs are good about working things out on their own.