Ideal for marine, salt and fresh water aquariums, along with environmental, water quality and wastewater testing. The Checker is a simple, accurate, and cost effective way to measure high ranges of nitrite.The checker is supplied with reagents for 6 tests. The reaction between nitrite and the reagent causes a greenish/brown tint in the sample. The checker is useful for initial measurements of nitrite when trying to establish good ammonia/nitrite/nitrate control. Suitable for all types of aquaculture, the ultimate aim is to decrease nitrite levels so that the low range of ultra-range nitrite checker can be used for optimum tank health. Nitrite can lead to tissue damage, illness and death of aquatic life, so regular checks can help aquarists identify rising nitrite levels before fish begin to suffer. Key Features: Nitrite levels from 0 to 150ppm Small palm-sized design Accurate from ±3 ppm ±5% of reading Dedicated to a single parameter Uses a single AAA battery Auto Power Off after 10 minutes in inactivity Built-in timer for timed reaction readings Box Contains: 2 cuvettes and caps reagent starter kit (6 packets of reagent) - 1 X 1.5X AAA battery Instruction manual