You'll need a ppm. pen and ph pen to keep you from going crazy .
I've found them both on ebay for 25.00 each or less . My ppm pen is a Sunleaves brand , my ph pen is a Milwakee brand . Both have been very very good to me . I love hydro. esp. my dwc / drip hybrids.
Peace
Crispi :jointsmile: