CW External Algae Scrubber - V2


Clear Water

An efficient and natural solution to excess nutrients and undesirable algae growth in your display aquarium

  • Natural reduction of excess nitrates and phosphates
  • Remove contaminants from the water column
  • Easy to harvest
  • Simple to install
  • Quality acrylic construction
  • Multi-directional input barb
  • Built-in light blockers 
  • Leak-free design
  • Suitable for saltwater or freshwater systems

Solve your nutrient & algae issues with an External Algae Scrubber from Clear Water Scrubbers. Algae scrubbers have been used for many years now with great results, and they can save you money and time with minimal maintenance and energy usage. They take advantage of algae's natural consumption of excess nutrients to allow for growth in a controlled environment, both aiding in nitrate and phosphate removal as well as discouraging nuisance algae growth within your display tank.  

Aquarists who are successful with Algae Scrubbers often find that they no longer need to use a protein skimmer or expensive phosphate removal media to combat nutrients because the scrubbers work so efficiently and can be added to almost any saltwater or freshwater system. As algae grows it will "lock" up nutrients and contaminants in its structure, allowing for their removal once the algae is harvested.

The Clear Water Algae Scrubbers have been redesigned to eliminate PVC pipes and fittings, making them able to be mounted just about anywhere with NO chance of leaks! Flow is also much easier to control and algae growth is achieved much faster thanks to the new tray design providing 100% screen coverage. Additionally, light blockers are now a built-in feature to prevent spillage, but they can be easily removed to check growth on the algae screen periodically.

Clear Water Scrubbers are an external design with a bottom drain, so they must be mounted higher than the sump of your tank, or higher than the full water level of your sump with an in-sump stand. The feed for the scrubber can be done with a stand-alone feed pump or manifold plumbed into the included 3/8” barb fitting. Water will then flow into the tray and down the algae screen that is blasted with a proprietary design of red/blue LED lights for optimal growth. Water will then drain into your sump through the 1” bottom drain installed in the scrubber.

Installation Instructions:

1. Mount the scrubber over the sump or above it elsewhere with either an in-sump stand, wall mount stand or whatever you want to use to hold the unit. It will need to be above the full line of your sump as the lamps cannot be submerged. They are splashproof but not 100% waterproof.

2. Hook up the scrubber with either a secondary pump or off a manifold.

3. To accurately determine the correct flow for the scrubber, the tray should be full of water but not so much that it is overflowing over the sides. Overflowing over the sides will increase the sound coming from the scrubber.

4. Initially the lamps for the scrubber should be run 24/7 to seed the screen. Once the screen is seeded, the run time on the lamps can be reduced if necessary. If you are running a UV sterilizer, shut it off for the 1st week or two as this will prevent the scrubber from seeding. The run time of the lamps controls the nutrient uptake for the algae. Cut back in 4hr increments until the desired balance is achieved.

5. Included in each unit is a bottle of iron/trace element replacement. This is a very concentrated dose of those elements. You should get an initial ICP analysis done so that you know where your levels are before starting the scrubber. The algae growing inside the scrubber will consume these elements to grow. This sample bottle is to replace those elements. Dosing amounts based on water volume can be found on Captiv8 Aquaculture’s website.

6. The initial seeding/harvest should take around 3-6 weeks. After that initial time frame, harvesting of the screen should be around every 7-14 days based on growth rates. You can either discard the algae or use it as food for your fish.


 Recommended Tank Size Dimensions Recommended Flow Rate Input Barb Size Main Drain Bulkhead
CW-50 50-100 gallons 8"L x 8"W x 9"H 150 GPH 3/8" 1"
CW-100 100-180 gallons 10"L x 8"W x 10"H 350 GPH 3/8" 1"
CW-200 180-400 gallons 12"L x 11"W x 12"H 450 GPH 3/8" 1"
CW-300 400-1000 gallons 15"L x 11"W x 14"H 600 GPH 3/8" 1"

What's Included?

  • V2 CW External Algae Scrubber

  • Sample Size Bottle of Captiv8 Aquaculture Isol8 MT Trace Element Solution

  • Roll of PTFE Thread Seal Tape