My problem with 15G is boil size just like brian_s so dilution is in my future. I wonder though, if fermenting in multiple fermentors might be a way around the de-aeration thing? If I diluted as it comes out of the boil kettle, the O2 in the dilution water would be a good thing for the yeast, no? Or maybe boiling the dilution water is just a good idea for sanitary reasons?