There is no better place to start than from the very beginning. In order to choose the best protein skimmer for your tank, you should know how they work and what it takes to effectively apply this highly-effective form of filtration to your saltwater aquarium. 

How a Protein Skimmer Works

A skimmer pump creates a dense foam by aggressively mixing air into your aquarium water. The pump ejects that foam into the body of the protein skimmer. Dissolved fish food and waste are attracted to surfaces of all those tiny bubbles that make up that foam. As the foam is condensed and pushed upwards through the conical-shaped body of the protein skimmer, it carries that fish waste and dissolved nutrients along with it where it finally boils over into the collection cup.

The collection cup eventually fills with nutrient-rich "skimmate" which can then be removed and emptied as an effective method of nutrient export. The remaining foam in the skimmer body is eventually diffused into cleaner water through a series of baffles or pipes before it drains back into the aquarium. 

  • Skimmate - It is the brown, smelly, waste-laden material that overflows into the collection cup. The end by-product of a protein skimmer.
  • Wet Skim - A type of skimmate that contains a large percentage of water. It will be liquidy and lighter in color relative to "dry skim". This is a result of higher airflow into the skimmer pump and larger bubbles in the protein skimmer.
  • Dry Skim - A type of skimmate that contains a low percentage of water. It's often very dark and viscous, sometimes taking on the consistency of mud. This is a result of tinier bubbles and less airflow into the skimmer pump. 


Protein Skimmer Collection Cup

What Does a Protein Skimmer Do?

A protein skimmer is designed to remove dissolved organics; fish food, waste, and other organic material that is dissolved into the water. Where your filter sock removes larger suspended particles of fish waste and debris, the skimmer removes microscopic (dissolved) particles before they can be broken down by bacteria. 

All organic material in your tank will eventually be broken down by bacteria and turned into ammonia, nitrate, and phosphate. Ammonia is highly toxic to your fish and elevated levels of nitrate and phosphate will fuel nuisance algae growth. The skimmer is an effective means of removing that organic material before it can be broken down by the bacteria and contribute to rising ammonia, nitrate, and phosphate. It essentially removes fish waste before it can pose any kind of threat to your tank. 

Types of Protein Skimmers

  • Internal Protein Skimmers: Protein skimmers that are designed for installation inside your sump and are powered using a single protein skimmer pump.
  • Recirculating Protein Skimmers: These skimmers utilize two pumps; one pump to feed the skimmer with water and a second recirculating pump that creates the foam. They can be installed either outside the sump (externally) or inside the sump (internally).
  • External Protein Skimmers: Water-tight skimmers that utilize a single pump and can only be mounted externally, outside of the sump. Generally larger in size compared to an internal skimmer and require a strong feed pump.
  • Hang-on Protein Skimmers: These skimmers hang on the edge of your tank and usually only have a single pump. 
  • Nano Protein Skimmers: Small skimmers that are designed to be submersed into the back filtration chamber of an AIO-style aquarium.  A miniature internal skimmer with just a single pump. 

Do I Need a Skimmer?

Protein skimmers are technically another form of mechanical filtration and you could maintain a saltwater aquarium without a protein skimmer using alternative methods of mechanical filtration. That being said, most saltwater aquarists use them because they are so efficient at waste removal and require minimal maintenance. 

Really the only situation in which a protein skimmer is not needed or beneficial is in low-nutrient reef aquariums which is a special type of tank that is purposefully maintained with undetectable levels of nutrients. These tanks engage a special technique called "carbon dosing" and rely on large refugiums for nutrient export.

How to Choose a Protein Skimmer

1. Where will it go?

This is the first bit of information you need to determine before you go shopping for a skimmer.  Are you going to hang the skimmer on the back of your tank? Install it in your sump or AIO filtration?  This will ultimately determine the type of skimmers you need to be looking at. 

2. How many gallons?

Next, you can narrow down your skimmer by matching your aquarium's total water volume with the manufacturer's recommended tank size provided with the skimmer. Each skimmer has a tank size rating/range that will allow you to narrow down the size of the skimmer that is appropriate for your tank. 

3. How heavy is your bioload?

Bioload is exactly how much waste your tank inhabitants are producing which is a direct result of how many fish and other animals you have in the tank. If your tank is full of fish and corals, you have a heavy bioload.  A moderately stocked tank is considered a medium load and a tank with only a few fish would be considered a light bioload.

This can be tough for a beginner because you just don't have a frame of reference. That being said, most tanks wind up with a medium to heavy bioload. Combine this with the manufacturer's recommendations for tank size and you can really zero in on the appropriately sized protein skimmer.

4. AC or DC Powered Skimmer Pump?

This is just a matter of whether or not you want a skimmer that has a controllable DC pump or a reliable AC pump. AC pump skimmers are generally more affordable but are limited in their range of adjustment because you cannot control the pump speed. DC-powered skimmers give the user a wider range of adjustments making it easier to dial in the skimmer and maintain optimal performance. If a DC skimmer is within your budget, that is always going to be the most ideal route. 

Should you choose an AC skimmer, just be sure you have accurately sized the protein skimmer to your particular tank size and bioload.  Contrary to what you might think, it's always better to undersize a skimmer than to get something too big because an oversized skimmer simply won't work.  

5. Do you want a recirculating skimmer?

Recirculating skimmers are what you might call "the bee's knees" of protein skimmers because they provide very consistent performance and offer a wide range of adjustments to the user. While this reliable performance is appreciated, they are also bulky and require the use of two separate pumps which means more electrical consumption, more cords, and more pumps to maintain.  

Most hobbyists start with a single-pump internal protein skimmer because they are the most economic option and the easiest to install and use. If you are planning on building a larger, heavily stocked tank and have the available space/budget, a recirculating skimmer is most certainly worth the extra expense because you can fine-tune the performance to accurately match your tank's bioload. 

Best for Beginners

Reef Octopus, Tunze, and AquaMaxx are the most popular brand of skimmers followed closely by Bubble Magus and Eshopps, all of which offer some great internal skimmers with an excellent track record among our customers. Here are Matthew's absolute favorite models for first-time tank owners, broken down by skimmer type. 

Hang-On Skimmers

Budget-Friendly Internal Skimmer

DC Pump Internal Skimmer

Protein Skimmer Diagram

Setup & Operation

Skimmer assembly can go one of two ways, extremely frustrating or super simple.  The best thing to do is take some time to watch videos on YouTube and do a little research about the particular skimmer you chose to get your head wrapped around the assembly and operation.  This will go a long way when the time comes to put it together. Some companies do a great job with instructions and user manuals while others, not so much. In most cases, you will be able to find a helpful article or video here in our Education Center and you are always welcome to call our customer service team with questions too. 

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