General Hydroponics 4-Piece pH Control Kit

The General Hydroponics 4-Piece pH Control Kit provides everything needed to manually test, raise, and lower the pH of hydroponic nutrient solutions. It combines a wide-range liquid pH indicator with General Hydroponics pH Up and pH Down, making it easy to monitor and correct nutrient-solution pH without a digital meter.

The indicator solution covers a broad pH range from 4.0 to 8.5. Many hydroponic crops are commonly grown within a nutrient-solution range of approximately 5.5 to 6.5, although the correct target depends on the crop, growing medium, and feeding program.

What’s Included

• pH Up: Potassium hydroxide and potassium carbonate solution used to raise low pH.
• pH Down: Food-grade phosphoric acid solution used to lower high pH.
• pH Test Indicator: Concentrated liquid indicator covering a pH range of 4.0 to 8.5.
• Test vial: Reusable vial for collecting and testing nutrient-solution samples.
• Color reference: Provides a visual comparison for determining the approximate pH of each sample.

Key Benefits

• Complete pH management: Test, raise, and lower nutrient-solution pH with one convenient kit.
• Wide testing range: Measures approximately pH 4.0 through 8.5.
• No calibration required: Offers straightforward visual testing without batteries or electronic calibration.
• Supports nutrient availability: Helps growers maintain an appropriate pH range for plant nutrient uptake.
• Useful meter backup: Provides a dependable visual reference when checking or troubleshooting digital pH readings.
• Beginner friendly: Uses a simple sample, drop, and color-comparison testing process.

How to Test and Adjust pH

1. Mix all plant nutrients and compatible supplements completely into fresh water.
2. Fill the included test vial approximately halfway with about 5 mL of the mixed nutrient solution.
3. Add exactly three drops of pH Test Indicator.
4. Gently mix the sample and compare its color with the included pH reference chart.
5. If the reservoir pH is too low, add a very small amount of pH Up. If it is too high, add a very small amount of pH Down.
6. Stir or circulate the reservoir thoroughly, then collect a fresh sample and test again.
7. Repeat gradually until the desired pH is reached.

Important: There is no universal per-gallon dosage for pH Up or pH Down. The required amount depends on source-water alkalinity, reservoir volume, nutrient strength, and starting pH. Add adjusters sparingly and always test between additions.

Safety and Storage

• pH Down is corrosive, and pH Up contains strong alkalis. Read all labels and Safety Data Sheets before use.
• Wear appropriate eye and skin protection and work in a well-ventilated area.
• Never mix undiluted pH Up and pH Down together or allow either adjuster to contact undiluted nutrients.
• Keep out of reach of children and pets.
• Store bottles upright and tightly sealed in a cool, dry location away from direct sunlight.