The Seachem MultiTest: Phosphate kit measures inorganic phosphate to less than 0.05 mg/L, producing a unique easy to read yellow-green-blue color range in marine and freshwater. MultiTest Phosphate performs over 75 tests and contains a reference sample for validation. Range: 0–3.0 mg/L. Precision: 0.001–0.1 mg/L.
More information about the Seachem MultiTest: Phosphate here