I found a page for you, you will find it beyond informative, my friends cat Carley has crystals, it is an on going battle, the poor kitty was adopted from a local animal shelter, poor little thing only has three legs, we nick named her Tripod, she is the mascot of our rescue, anyway, Please read
Diet, FLUTD, & Urinary Stones I hope that it is helpful to you. Tripod, had to be placed on a special diet which has helped greatly, expensive but helpful