I also batch sparge and saw a big improvement when I sparge in two steps. So, drain the tun, put in half your sparge water, stir like hell, drain, dump in the remaining sparge water, stir like hell, and drain. Just make sure your sparge water is under 168. I'm at 85% mash efficiency after my 5th all grain batch. I also am using rodi water, 1/2 tsp CaCl, and 2% acid malt in my mash. Hope this helps!