Have a look at the pictures of the plants below and tell me what you think my problem is:
These plants are just over 3 weeks out of the seed and this problem showed up about 3 days ago. I have had some problems with wild pH fluctuations for about 2 days (electronic meter reported pH 3.4 to 8.5) but it has been stable within an acceptable range (5.8 to 6.4) for 4 days since then but the problem continues to get worse. I'm growing in a homemade aeroponics system (Rubbermaid tub) using Humboldt Nutrients Oneness approx. 600ppm. They have been under a 400w HPS light for 24 hours a day (changed photoperiod to 18/6 today). Strange thing is, the not all of my plants have this problem - only 4 plants out of 10. The strain shown is Great White Shark. Thanks for your help.
These plants are just over 3 weeks out of the seed and this problem showed up about 3 days ago. I have had some problems with wild pH fluctuations for about 2 days (electronic meter reported pH 3.4 to 8.5) but it has been stable within an acceptable range (5.8 to 6.4) for 4 days since then but the problem continues to get worse. I'm growing in a homemade aeroponics system (Rubbermaid tub) using Humboldt Nutrients Oneness approx. 600ppm. They have been under a 400w HPS light for 24 hours a day (changed photoperiod to 18/6 today). Strange thing is, the not all of my plants have this problem - only 4 plants out of 10. The strain shown is Great White Shark. Thanks for your help.