Aeroponincs. 8" big plants. PH at 5.5- 6.0, ppm is at 440.
Any ppm ph suggestions?

The following is a paragraph I got from "http://www.cannabis.com/growing/nutrient_formulations-MisterIto_beginner_nutrient_flushing_formula.html"
"I maintain my solution at 500-1000ppm, depending on growth stage. Young, established seedlings or rooted cuttings are started at 500-600ppm. The TDS is increased to 800-900ppm during peak vegetative growth. During the transition from early to heavy flowering, TDS is further raised to 1000ppm. It is then reduced to 400-500ppm during the final 2 weeks of flushing. I maintain my ph between 5 and 5.5, which usually requires little to no adjustment due to the high buffering capacity of the organic supplements."

When I have seedlings I usually have a very mild solution with around 400ppm and when they start to grow I raise it to 500-600. Unless your plants are at the vegetative stage you should not go much higher, as you will definately overfeed them. The otpimal pH throughout the entire growth cycle is from 5.0-5.5 And water should be changed at least every two weeks. I had a problem with slow growth about 2 weeks after the seedlings emerged and as soon as I changed the water they grew extremely fast. Hope this helped