Hi, I just found out today that my 14 yr. old cat showed crystals in her urine, I just took her for her annual visit yesterday. The vet told me to feed Misty a lower magnesium diet and mentioned Science Diet Hairball Senior. I am now feeding her Purina One Senior but the vet said the magnesium was not listed on it so didn't know how much was in there. The canned food I'm feeding her now is ok but it is the dry the vet is interested in. Do you know of any other dry foods I could try that is low in magnesium in case Misty doesn't like the SD. Thanks.