Thanks for the reply, the concentration is very high. You hit the spot ritght on the bulls eye with that one. 21-0-0. Nothin but N. Funny because I used to put vinegar in my hydro system about on drop and it would bring the ph right back to normal. I did some research on the net for household products to bring down ph in soil and found nothing except the use of Ammonium nitrate. What meter do you speak of?