These simple and inexpensive test kits usually contain the following:

• A phial for holding a measured sample of nutrient solution.

• A bottle of re-agent to add to the solution.

• A colour test strip, which is compared to the sample to ascertain the pH level.

Some test kits cover a wide pH range (4 — 10) but others are available for horticultural use. These cover a smaller range around pH 6, which are a lot more accurate.