Hi Everyone
Just to clarify, most cats get struvite crystals, and this is the area where in the past ash would be involved. Ash is comprised of minerals, hence looking for "low ash" was a way of the past. You would need to concentrate on the Magnesium content. These struvite crystals are different than what was mentioned in the previous post, as these are calcium based not magnesium based, and although raw may be an answer, it IS dependant on how much bone is included in the diet. This is NOT a factor in realtion to using raw for struvite crystals, as it is ideal diet for struvite. I have included a great article, however you may want to check with your vet, as I believe calcium oxylate crystals grow in a variety of PH, not just over acidic.
http://www.peteducation.com/article....articleid=2729
Good luck