What the General Hydroponics pH Control Kit Contains
Four pieces that cover the whole job. 8 oz of pH Down, which is food grade phosphoric acid. 8 oz of pH Up, built on potassium hydroxide and potassium carbonate. 1 oz of pH Test Indicator, and the vial you read it in. Worth knowing what those chemistries carry with them. Phosphoric acid brings a little phosphorus into the tank, and the Up side brings potassium. Both are harmless at these volumes, but they are real. The sequence matters as well. Mix your nutrients into fresh water first, let them go in properly, and only then adjust. Adjusting before the nutrients are in means doing the whole thing twice, because the feed moves the pH on its way in.
Reading a Hydroponic pH Test Kit by Colour
Fill the vial to about halfway, roughly 5 mL, then add three drops of indicator and compare the colour against the chart. The indicator covers 4.0 to 8.5, and most crops want the solution somewhere between 5.5 and 6.5. Adjust in small amounts, stir or circulate, and test again before adding more. A capful is almost always too much on a small reservoir. The honest limit is that a colour is a band rather than a number. Holding a target to a tenth of a point is a job for a meter. What you get instead is a tool with no calibration, no battery and no probe to dry out. Both concentrates are corrosive, so wear eye protection and never mix them straight together.
Key Features
- Four pieces, whole job: 8 oz pH Down, 8 oz pH Up, 1 oz indicator and the test vial.
- pH Down is phosphoric acid: Food grade, and it brings a small amount of phosphorus with it.
- pH Up is potassium based: Potassium hydroxide and potassium carbonate, so it carries potassium.
- Reads 4.0 to 8.5: Three drops of indicator into a vial filled to about 5 mL.
- Target 5.5 to 6.5: Where most crops keep nutrients available rather than locked out.
- Adjust after nutrients: Feed moves pH as it goes in, so adjusting first means doing it twice.
- Small amounts, then retest: A capful is almost always too much on a small reservoir.
- Nothing to calibrate: No battery, no probe to dry out, and no monthly two point routine.
- A band, not a number: If you need to hold a tenth of a point, a meter is the right tool.
- Both are corrosive: Wear eye protection, and never mix the two concentrates directly.
Technical Specifications
| Specification | Value |
|---|---|
| Brand | General Hydroponics |
| Part Number | 722080 |
| Product | pH Control Kit, 4 piece |
| Contents | 8 oz pH Up, 8 oz pH Down, 1 oz pH Test Indicator, test vial |
| pH Down Derived From | Food grade phosphoric acid |
| pH Up Derived From | Potassium hydroxide and potassium carbonate |
| Indicator Range | pH 4.0 to 8.5 |
| Test Method | 3 drops of indicator per vial filled to about 5 mL |
| Target Range | 5.5 to 6.5 for most crops |
| Sequence | Mix nutrients into fresh water first, then adjust pH |
| Dosing | Add a small amount, stir or circulate, retest, repeat |
| Calibration | None required |
| Power | None |
| Safety | Corrosive. Eye and skin protection, work in a ventilated space |
| Do Not | Mix undiluted pH Up and pH Down together |
| Storage | Sealed and upright, cool and dry, away from children |