Scientific cat litter?

I saw this stuff once in a tiny pet store in the area & now I have saw an ad for it in Cat Fancy. I think it sounds too good to be ture. They say that it can help you tell whether or not your cat is ill. Anybody tried it?

there is a litter to help detect uti

I got a flyer in the mail on this one too. The way I understood it the litter has a color change granule that detects the acidty level or lack there of in the urine. One of the causes of Feline Lower Urinary Tract Disease is too much acidity or alkalinity of the urine. This may be helpful for a cat that has a past with urinary trouble. I'm not sure it's necessary for a healthy feline.

I'm interested in opinions on this also.