I use a digital Milwaukee ph600. I think they are on ebay for around 20 bucks plus they come with a small pk of calibration solution. I would advise to always get extra cal solution and keep a little in the cap to keep the electrode wet.

IMO im not seeing any overfert going on in the pics. No burnt tips, etc. Im still going with over/under watering. Most likely under.

Also check out this thread. Its kinda old but it has some good info plus hes using the same soil. http://boards.cannabis.com/grow-log/...s-old-log.html
pushit Reviewed by pushit on . Hard, crusty, sticky leaves. Yet soil is dry and seperating from pot sides!? Help pls Hi all. This is my first time grow. Im growing northern lights in bio bizz all mix soil in 18 litre pots in a Wilma system. Im growin in a 1mX1mX2m grow tent with a 600w hps light, a carbon fan filter running 24hrs and a 6" oscilating fan going in the 18 hrs of light (using 18/6). The temp is always between 75-80 and humidity around 50%. Its day 25 since i planted and i noticed one of the plants biggest leaves had gone crinkled, hard and was cracking althought it had not lost any colour Rating: 5