I am having a tough time finding "Super Phosphate" in my neck of the woods. Any suggestions? I do see that Lowes/Home Depot have it in 4 lbs. bags, but that is not practical or economical (but it may be the only course). I need 40 to 50 lbs since I would be mixing it with my 10-10-10 which I just got (and that was a 50 lbs bag).
