I was using Tiger Bloom for the last month or so and i'm pretty sure it helped lower my pH down from the 7's. Not sure if ever made it down to the 6.1-6.5 range but the plant was looking healthy so after a while I kinda stopped dwelling on pH. Even the guy who sold me the Tiger Bloom at the hydroponics store I bought it at told me not to stress about pH if I was going to be feeding it with Tiger Bloom.Have you regulated the pH to 6.1 - 6.5?