Has anyone tried this product. I have around 6 blueberry bushes with yellow of leaves thats Im sure is ph related. I have does them up with sulfur to lower ph. In knowing that sulfur takes a few monthes or more to lower ph I came across this product. I have been looking high and low for copperas. This is a great product that has become less availabe. SO the Hi-yield iron plus has less amonicable nitrogen 13% compared to amonium sulfate which has 20%. I actually think this would be a good thing and would lessen the chances of nitrogen burn. I try and fertilized my bushes in 3 phases. I think this in 3 small doeses would be great and would lower the ph much faster with less harm.