Your vet is correct, any product that has aluminum in it binds phosphorous. Some cats find the tums less offensive than the amphogel. Another product that can be used is Alternagel, it is similar to the Amphogel. The bad news is that all the phosphorous binders taste awful to cats whether OTC or prescription, phosphate binders however are very very important. There are things like epikatin and azodyl that may taste better but they are prescription. I hope this helps, best wishes.