Hydroponics 4-Way Test Kit, Maintain proper nutrient balances and achieve optimum growing conditions in soil-less systems. Test for pH and three key nutrient factors, Applications: Soil, Environmental Education, Model HP-1, approximately 50 tests each.
Each Roll Includes 15 Feet Of Paper Spooled On A Tightly Sealed Plastic Dispenser. The Paper Provides Sharp, Clear Color Changes For Easy Comparison To The Included Color Chart.