The Seachem MultiTest Copper Test Kit performs over 75 tests and contains a reference sample for validation. Copper kits are usually of two types: compleximetric or titration based. Some kits measure only ionic copper and others measure both ionic and chelated copper. This kit uses a highly sensitive catalytic compleximetric based procedure to measure all types of copper to less than 0.01 mg/L in marine or freshwater aquariums. Colour ChartAll Seachem MultiTest test kits come with an easy-to-read colour chart. It features a 5cm viewing window to help isolate colour and match as closely as possible to the test sample Opaque Multi-Cavity Test PlateAll MultiTest test kits are read from an opaque white test plate. The sliding colour chart along with the six-cavity test plate allows for easy reading and comparisons of several samples at the same time.