Algae turf scrubber is what I have used for the past 20 years, I built my own after reading a book Dr. Addy at the Smithsonian wrote.
It basically has brighter illumination than the main tank, causing algae to grow there before it does in the main tank, thus soaking up all the available nutrients for plant growth. The algae can be easily harvested for food, or thrown down the toilet. Many different kinds of algae works in these systems. Mine uses a dump bucket that creates a wave every 10 seconds.