Turf Algae Scrubbers are one of the coolest, easiest, and most effective ways to export nutrients (nitrate and phosphate) from your saltwater aquarium. Like a refugium, a turf scrubber relies on the growth of algae as a means of sequestering nitrate and phosphate from the water. Upon harvesting of said algae, nutrients are effectively removed from the aquarium. 

While both a refugium and turf scrubber use the same concept of natural nutrient export by way of algae, they go about it differently.  Instead of introducing macroalgae species like Chaetomorpha, Caulerpa, and Gracilaria, the turf scrubber actually grows a mat of light green hair algae that does not need to be introduced. The algae will already have been introduced into your tank alongside your substrates and livestock, it's just about providing the right environment for that algae to grow prolifically.  

The modern era of turf scrubbers has come a long way in terms of design and manufacturers like Foursquare Aquatics have really streamlined the use of scrubbers in an aquarium. In days past, DIY scrubbers were the only option and often ended up looking terrible, prone to leaks, and sometimes even hazardous. 

Foursquare Aquatics takes a very modern approach and has refined their APIS external turf scrubbers to be easy to implement and maintain as well as safe to use and