Below is a post I made elswhere on the site. Might have some helpful info for you.
Well, my guy must have detected the cranberry powder because he stuck up his nose, so I stopped putting it in. I also read something yesterday about magnesium in the wet food, and which foods are recommended. So I know I am feeding him right, the right diet creates acidic urine. Also, I just ordered some tablets that create an acidic urine. I will attach both of these articles if I can.http://www.swancorner.com/feilineurologicsyndrome.html
this is the site that discusses food and FUS, CarponTM
A Natural Urinary Acidifier
Treats and prevents Feline Lower Urinary Tract Disease by acidifying urine and breaking up struvite crystals. Contains a natural acidifier extracted from berries. Tablet form.
Carpon100 tablets$19.30 + s/h
and above is the name of the product I ordered, developed by Belfield Pet Food Research Center
by Dr. Wendell O. Belfield
I hope you can find these links.