 The Microtox Model 500 is a laboratory-based photometer that measures acute toxicity.This analyser is a temperature-controlled, self-calibrating biosensor measuring system that uses the bioluminescence of "Allivibrio fischeri" to determine the toxicity of contaminated water, or elutriates of contaminated soils and sediments.Microtox Continuous Toxicity Monitor (CTM) is a site-specific Microtox analyser that continuously measures the toxicity of a water source and provides results instantly.