The ALGE-BARTs contain a ball, dehydrated medium, and geo-textile. Add water sample until the water reaches the top of the textile. Below the ball, there is a layer of textile into which the algae can grow. Nutrients to support algal growth diffuse into the water sample from dehydrated medium deposits in the base of the tube.
Algae include various plant-like microorganisms, which can photosynthesize using light as the energy source for growth. Several types of algae can grow in the ALGE-BARTs, including: Grass-Green Algae (Chlorophyceae), Blue-Green Algae (Cyanobacteria), Desmids, Diatoms, and Euglenoids. The ALGE-BART can be used as a simple presence/absence (P/A) test capable of indicating, to some extent, the population size and the types of algae present in the sample.