The great thing about a scrubber is that it grows exactly what many fish eat naturally. Even fish that you think would not eat algae, such as some cichlids, will do so if the growth is living. But many freshwater and saltwater fish and other animals love it. Green hair algae is especially popular, but some of the lighter brown slimes are also well-received.

It’s a similar ecosystem to what you find in a garden, where you eat the growth then compost the woody plants that grow that new growth; you produce your produce and buy less food from others. The entire system becomes much cleaner and more streamlined. Same with algae scrubbers in aquariums; the more you feed from your scrubber, and the less food you add from the outside, the lower the nitrate and phosphate will be in the water.

Some people worry that if you don’t remove the scrubber growth and throw it away, you won’t remove nutrients from the water and the nitrate and phosphate levels will increase. But the answer is to add less food from the outside, and replace it with the fresh living growth from the scrubber. Nutrients will flow from the fish to the scrubber and back to the fish, and the fish will use those nutrients to grow bigger, and eat even more, which takes those nutrients out of the water. And since you are adding less food (nutrients) from the outside, the nutrients (nitrate and phosphate) in the water goes down to a lower overall level.

How do you feed scrubber growth to your fish? Well with any scrubber, you can remove the growth with your hand if the growth is green hair algae, then you can put the growth in the water freely or with a feeding clip. If you have a HOG or DROP model, you can put the whole thing in for the fish to eat from. If you have a waterfall such as a RAIN model, you can put the screen into the water, or you can remove the growth from the screen first.