Having worked in the aquarium industry for the past two decades (and then some), a question I often hear is "which protein skimmer should I get for my tank?"

Seems like a simple enough question. Truth is: it’s not.

There are literally whole chapters in books dedicated to this very question. Fortunately, we’ve read many of these books. Through our research and experience we’ve developed a deep understanding of all the various skimmer types available and what works best in different scenarios. With a little research and experience, you will, too.

This article should help you get off on the right foot.

To be clear: we are not going to declare one skimmer superior over another (check out the product reviews on our site for that). Our goals are to expose you to the different types of protein skimmers we carry, explain how to find the right skimmer for your aquarium and show you how to set one up and maintain it once you do.

Types of Protein Skimmers

There are four basic types of protein skimmers available. Some skimmers, it should be noted, can be used in more than one application, meaning they can be used as a hang on OR in-sump skimmer (for example).

  1. Hang On Protein Skimmers
    As their name implies, hang on skimmers hang on the back of your aquarium. These types of protein skimmers are useful for aquariums that aren’t running a sump. The skimmer will conveniently hang on the rim of an aquarium similar to how a power filter hangs on to a tank. Generally speaking, hang on skimmers are designed for smaller aquariums (100 gallons or less). AquaCCPR and Deltec are a few popular (and well-reviewed) brands on our website.
  2. In Tank Protein Skimmers
    In tank skimmers take up minimal space so you can place them right in your aquarium. Despite their slim size, they do an effective job removing organics from aquarium water. The most popular in tank protein skimmers are designed for nano aquariums. Check out the AquaticLife Mini and the Tunze Nano or Reefpack for examples.
  3. In Sump Protein Skimmers
    In sump skimmers are designed to sit within an aquarium system’s sump. It is within this sub-skimmer category you’ll find the most options available in terms of size and style. Prices range from a mere $40 all the way up to $3400, depending on your needs. AquaCDeltecReef Octopus and ASM are prime examples of in sump protein skimmers.
  4. External Protein Skimmers
    External protein skimmers, as you may have guessed, run externally to the sump of your tank. Water from the sump is fed into the external protein skimmer. "Clean" water is then returned from the skimmer to the sump. If you’re in the market for an external skimmer, consider Deltec, Reef Octopus, Precision Marine Bullet or AquaC EV.

How protein skimmers create bubbles

The main goal of all protein skimmers is to create very small bubbles within the skimmer to better attract dissolved organics. Different skimmers use different methods to produce these "micro" bubbles.

One of the most popular ways to produce bubbles in a protein skimmer is by using a venturi valve. Venturi valves use the force from water in the skimmer pump to pull air into the protein skimmer.

To "chop" incoming air into even smaller bubbles, some manufacturers include pinwheel or needlewheel impellers in their skimmer pumps. As bubbles pass through the impeller, "needles" or "pins" shred incoming bubbles into micro bubbles.

If your skimmer pump doesn’t include this specialized type of impeller, upgrades are available. Coralvue and AquaMaxx both make affordable needle wheel impellers for Sicce PSK skimmer pumps.

AquaC uses a patented technology called "spray injection" to produce the bubbles in their protein skimmers. Precision Marine uses a "beckett injector" in their line of Bullet skimmers. Air-driven protein skimmers are also available but have become less popular through the years.

How to choose the right protein skimmer

If you’re not running a sump as a part of your aquarium system, you will need to decide between a hang on or in tank protein skimmer. Often the amount of space you have in/outside the tank is the determining factor for which type you’ll ultimately go with.

If you are using a sump, you’ll have your choice between all four types. Most sump users opt for an in sump or external protein skimmer.

You’ll want to take two important measurements before purchasing an in sump skimmer. First, measure the free space in your sump to ensure you’ll have enough room to accommodate the footprint of the protein skimmer you’re considering. Next, measure the maximum height you have available for your potential skimmer, taking into consideration the extra space needed to remove the collection cup. Knowing these measurements before you buy lessens the likelihood you’ll have to return the skimmer for another, more appropriately sized model.

How to setup a protein skimmer

While there are only four major types of protein skimmers, there are countless sizes and styles. To encompass all here would be difficult; we’ll instead hone in on the steps common between each type. We encourage you to follow the instructions included with your skimmer, if any. If you need help, contact us.

  1. Rinse your new skimmer thoroughly inside and out with warm water to remove any dust or residue left from manufacturing. If you’re using a hang on or external skimmer, you only need to rinse the parts that will have water in them.
  2. Place the skimmer in the appropriate location. Be sure it is sitting level. You may need to put some saltwater into the skimmer to help it sink (in sump) or before turning on the pump (some hang on models).
  3. If your skimmer did not come with the pump(s) preinstalled, connect the pump(s) to the skimmer inlet along with the feed tube (if applicable).
  4. Plug in the feed pump (if applicable) and adjust the water level within the protein skimmer.
  5. Now plug in the pump used for bubble production. Adjust the flow of air into the skimmer. Double-check the water level within the skimmer and adjust using the ball valve, riser tube or gate valve included with your protein skimmer.

Your skimmer should now be up and running. You’ll know it’s functioning properly if you see bubble production in the skimmer body. Keep an eye on your new skimmer for the next few hours to monitor its performance. You may need to raise or lower the water level inside the protein skimmer and increase or decrease the amount of air going into the skimmer for optimal operation. You may also raise or lower the collection cup. These little adjustments can make a big difference so don’t be afraid to fiddle with the settings. It’s almost important to point out many skimmers go through a "break in" period that lasts hours to weeks so you’ll want to keep a watchful eye on your skimmer, especially during these early stages.

How to maintain a protein skimmer

The following steps are an excerpt from fellow MarineDepot.com employee Robert Farnsworth’s article, How to Clean Aquarium Equipment.

  1. Turn off your protein skimmer and unplug the pump from the wall to avoid electrical hazards. Next, drain the skimmer in order to remove it from your aquarium, if applicable. Remove the pump and inspect all plumbing fittings for damage. Any o-rings or gaskets should be removed and inspected for cracks. You can apply silicone-based lubricant to extend the life of o-rings or gaskets before re-installing.
  2. Rinse the collection cup and skimmer body in RO/DI water to remove any sludge. Check venturi tubes and plumbing parts for any clogs. Rinse clean.
  3. Cleaning the pump is the most important part of this process. While the tips herein apply mostly to submersible pumps, external pumps are maintained much in the same fashion. First, carefully remove the impeller cover and inspect the impeller for any damage. Proceed to soak the pump and all components in vinegar, D-D Ezeclean or a similar solution in order to remove the calcareous buildup. I typically remove any sealing gaskets or o-rings before soaking. Take caution with impeller shafts as many are made from ceramic and can be fragile. Tooth or other small brushes are great for removing persistent build up and calcium deposits inside the pump.
  4. Finally, rinse all parts thoroughly in RO/DI water and reassemble the skimmer. Keep in mind you may have to let the skimmer "break in" again after cleaning the body and cup. Most skimmers require a little bit of time, often referred to as the "break in" period, to begin collecting adequate amounts of foam.

You should empty your collection cup weekly and clean it along with the protein skimmer neck/body to keep everything sludge-free. Even if your skimmer is equipped with a drain fitting for remote collection of skimmate, you should still clean the cup and body regularly to maintain maximum performance.

If you have any questions about protein skimmers, please do not hesitate to call (1-800-566-FISH) or write us. We can help walk you through skimmer setup if you’re stuck or make recommendations based on your individual tank specs.