After the last step, I fed the starter again:  100 grams starter, 100 grams tap water (the starter was fermenting easily enough, so I switched), 100 grams unbleached bread flour. Here's what the starter looked like before feeding: 001Starter after the fifth feeding

After feeding I marked the container again: 002

Here it is the next morning: 003Later that day the starter acidulated and bubbled nicely: 005

As soon as I post this I'm going to mix a levain (sponge) from the starter and let it ferment overnight; tomorrow I'll post the recipe for the easiest focaccia you'll ever bake.

LEVAIN (SPONGE)

100 grams active, bubbly sourdough starter

100 grams room temperature tap water

100 grams unbleached bread flour

Stir the ingredients together in a medium bowl and cover with plastic wrap.  Let the levain ferment until well risen, about 8 to 12 hours.

I'll post the rest first thing in the morning in case you're going to make the sponge tonight.