Thank for the responses,

I have lowered the PH down to 5.5 - 5.8. The grow medium is the clay pellets, they are approx .5 inches in diameter. I am currently running the system 24/7 If I am going to need to cycle it on and off where do I get a timer that will handle that many cycles per 24 hours.

Also, I didn't get much response regarding the air stone. would it be an advantage to airate that water a bit better?

Thanks again.

JRF