They are all about the same as long as it is water soluble. One company Pro-Sol use to make all of it and package it for different re-sellers.

Where are you - most Co-Ops carry some form of it. Also the fisheries outfits have it for delivery. I get mine from Greg Grimes when he comes through town. I also use some 0-46-0 pelleted on platforms and some 13-13-13 and once in a while some 45-0-0 when more N is needed.