ppm = parts per million. The instructions on your meter should tell you how to convert the number you are seeing into ppm.

New clones don't like a lot of light. Back your lights way off until you start seeing healthy growth, then move them closer.

Try the house lights without the MH on, then try the MH without the house lights on, see if the lights still flicker. A flicker can often be a sign of a loose connection or loose bulb, so make sure all your connections are good and your bulbs are screwed in tight.

PC :smokin: