Blue buffalo warning

So I've been feeding my cats blue buffalo for 3 years.. Well cont to find out after spending $2000 on vet bills that food can cause crystals and uti in cats since they don't really research there products since there a new company now I had to switch therr food and my one cat Sylvester who has the crystals has to be on wet food only and my gills are on dry food but for uti.. Herr are my babies boy Sylvester black and white one lol all black girl is phoebe and other one is nixie. And yes he fixed