I occasionally get some diacetyl, especially in darker ales. I'm sure it's not contamination or equipment sanitation issues. I originally thought that it may be caused by fermenting in the 62-64 degree range, but don't really think that's the problem, because a longer fermentation time should take care of that, and I've had some slight diacetyl even after primary fermenting for 2 weeks and secondary for another 10-11 days. I recently got water quality results and saw that my calcium levels are only in the 8-14ppm range, and I've read that it should be a minimum of 50. Could low calcium cause diacetyl issues, and would adding some gypsum take care of this. Thanks.