I’ve had several CKD cats and never fed the prescription food. One, because it’s not palatable for alot of cats, and two, it’s low protein and a cat that is leaking protein due to CKD doesn’t need less. There has been such a controversy over that for many years and some vets still don’t get it. The prescription people just keep “feeding” (so to speak) them the same old drivel. Read
Dr. Lisa’s take on prescription diets. Also, typically, if you are feeding a prescription kidney diet, you shouldn’t have to add binders.
What I always did, using Tanya’s, was select high quality foods that were as close to 0.6%P on a dry matter basis that I could find. There are great
food tables on Tanya’s to help you with this and they also show sodium (important in CKD cats) and carbs (for FD). I didn’t use phosphorus binders (I used aluminum hydroxide) until the P hit 6. You don’t want to use them any longer than you have to as they can potentially cause constipation and also aluminum toxicity.