How much feed? The ACV is not at all necessary, but I'd not toss that batch. As long as you used at least a couple quarts of feed, it should be ok. Remember, you're not trying to make pickles, just introduce a bit of good bacteria and yeast into it. If left open to the air, the feed/water will pick up plenty of stuff just from the air. When it starts bubbling, you can start feeding it. Or, you can start feeding it even before then. It's not rocket science. I've started a fresh batch, and fed some out the day it's started, held some back to inoculate the fresh feed and water added. By day 3, it's fermenting well.