My girls are on HPW (original), and no added supplements are needed. I have read on here somewhere that you can add 3/4 tsp of Now (brand) Calcium Carbonate to the batch so as not to worry so much with the ca/ph ratios. I don't know how many do this, I haven't yet, but think about doing it for next batch. I really haven't just made up my mind about it, so haven't gotten any. I just use variety of f/v combos, I try to lookout for the ca/ph ratio best I can, but my girls won't eat some of the f/v if they don't like it.