Hi Juan, switching to feeding with a lower protein flour shouldn't damage your starter or cause it not to rise as well, unless perhaps you switched to using a bleached flour. In fact, your starter will get a slightly better meal from a lower protein flour because the protein and starch in wheat flour are inversely proportionate, which means the higher the protein, the lower the starch content. Since starch is what your starter consumes and ferments, it gets a bit more nourishment from a lower protein flour. 

That being said, you may have noticed a change in consistency when you switched flours, since bread flour will absorb more liquid than a lower protein flour. It's possible that the rise didn't seem as robust with the lower protein flour because the starter was thinner in texture and wasn't holding on to the fermentation bubbles quite so efficiently. 

If you changed from feeding with a 1:1:1 ratio to a 1:2:2 ratio in order to flush out the remaining low protein flour, this would have slowed down the ripening process; causing your starter to take longer to reach its peak. And changing flours can generally result in a little sluggishness because the starter organisms need time to adjust to the new variables they are presented with. 

The good news is that none of the changes you made should cause any permanent harm to your starter, and I would expect a few days of twice a day feeding at room temperature will get it doubling again. During this time take care to replenish (feed) your starter when it's at its peak of rising, or just beginning to fall, which will keep yeast activity vigorous. Allowing the starter to fall significantly between feedings tends to lead to sluggish yeast behavior. 

I hope this helps! Let us know how it goes. 

Barb

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