Aquarium Fish

Protein Skimmer - What is it?

What is a Protein Skimmer?

A protein skimmer, also sometimes referred to as a foam fractionator, is a piece of aquarium equipment that is primarily used in saltwater aquariums in order to remove dissolved organic compounds (DOC) and other harmful substances that if not removed can breakdown in the aquarium or filter adding to the biological load on an aquarium. Protein skimmers remove these hydrophilic substances completely from the water using air bubbles that are collected in a collection cup. As air and water are mixed in the skimmer chamber the bubbles rise and take with them the dissolved organics that are attracted to the bubble surface. When the bubbles with the proteins, amino acids and other nasty stuff bubble up the tube into the collection cup they are completely removed from the aquarium.

Unlike a mechanical filter that just traps solids but still exposes them to the aquarium as the water continues to flow over them all the while these solids are breaking down and adding to the total bio-load on a tank. Skimmers could possibly be consider one of the most significant advances for the saltwater hobbyist.

protein skimmer

Think about the ocean for a minute. You know how as the waves crash on shore you will sometimes notice sea foam? This is similar to the way protein skimmers function. Air is mixed with water and then the dirty bubbles (foam) are placed on shore, only with a protein skimmer this foam is removed from the system via the collection cup.

Protein Skimmer Video

Protein Skimmer Benefits

  • Skimmers increase the dissolved oxygen levels and redox potential in an aquarium

  • They remove dissolved organics before they get a chance to breakdown and become a food source for nuisance algae

  • By removing dissolved organics the aquarium water clarity does not age or yellow as quickly since the DOC buildup is less allowing light to penetrate deeper into the tank for the benefit of corals and other inverts.

  • Can help lead to a more stable pH since less dissolved organics are in the system.

  • Overall improvement in the health and vigor of the animals in the aquarium since their wastes are being removed from the system via the collection cup.

Although it is my opinion that a protein skimmer's positives far outweigh the negatives I still have to mention that there are some drawbacks to using a skimmer.

Protein Skimmer Drawbacks

  • Can be very to extremely expensive

  • They can remove beneficial bacteria as well as phytoplankton and other desirable organisms from a system.

  • They can remove trace elements that may need to be replenished or supplemented, such as Iodine. Other elements are most likely removed as well and if partial water changes are not practiced on a regular basis your system could become unbalanced chemically, i.e. not have the proper proportion or ratio of trace elements to major elements. Regular partial water changes with properly mixed saltwater will prevent this from happening.

Do I really need to a protein skimmer?

skimmer collection cup One of the first questions new saltwater hobbyists seem to ask is whether they really need a protein skimmer for their first setup. Especially when they start to shop for a skimmer. The short answer is NO, you don't have to run a protein skimmer on your setup. There are many hobbyists that run successful systems without them. However, these hobbyists also realize the importance of regular partial water changes for the aquarium and how important water changes are to the health and well being of the animals in their care.

By not running a protein skimmer you really do need to stay on top of those water changes. Otherwise you will start to see nuisance algae growths cropping up all over the place, especially if you have high output lighting like metal halides, T5's or VHO fluorescents. The initial expense of getting a good protein skimmer is justified in the peace of mind it gives the hobbyist and the overall water quality improvement it can provide. I'm telling ya, once you see and smell your first collection cup full of gunk that is removed from your aquarium you will be hooked on skimmers. The way most systems are stocked nowadays (rarely are they understocked) skimmers should be pulling out at least a cup full of skimmate from the system daily. Do you really want that amount of dissolved organics accumulating in your tank in between water changes? Me neither.

Running a system without a skimmer and without live rock would seem to be someone that is just trying to A) set themselves up for failure or B) they like bashing their heads against walls. If you're planning on a system without live rock and no protein skimmer I would simply ask, why? Make the system as easy to maintain as possible and chances are you will be able to enjoy it more.

Skimmer Types

Really? You want to cover this? Ok, if you say so. If your mind starts to glaze over mid-read, you've been warned. Basically, the object here is to find the best way to create lots of tiny bubbles and to provide the optimal contact time with the organics so they can attach to the bubbles and then rise as a foam into the collection cup. The body style of the skimmer can be an important design consideration when utilizing any of the methods of creating bubbles. Here are a few ways to make bubbles:

Co-current skimmers: These were some of the first used and they had an air stone at the bottom of the chamber providing the air bubbles. The air bubbles rose vertically and were collected into a cup. Actually, these skimmers even today are good skimmers. The wooden air stones (finer bubbles) just have to be replaced regularly.

Counter Current skimmers: The air/water mixture is forced through a counter-current of aquarium water in the body of the skimmer. This is supposed to give a longer contact time for the bubbles to attract the organics.

Venturi skimmers: These use a venturi valve to mix in air with the water. These valves are usually situated on the intake tube coming into the skimmer.

Needle Wheel Skimmers: These use a spoked wheel that spins and chops up the incoming water producing fine bubbles. There are also mesh wheel skimmers that function in a similar way.

Spray Induction: As the aquarium water comes into the skimmer it is forced through a spray nozzle that creates a lot of tiny bubbles.

Downdraft and Beckett: These skimmer types use proprietary parts to mix the air and water to create the glorious bubbles we love. Some of the larger protein skimmers are these types of skimmers.

Knowing how a skimmer creates it's bubbles could be a consideration for the hobbyist. Some are more popular than others. It really comes down to doing your research, just like everything else in this hobby. Are you going to pick a skimmer just because it's a downdraft skimmer? Of course not. You are going to come to a decision based on reviews from other hobbyists or first hand experience with a unit.

Skimmer Maintenance

When shopping for a protein skimmer it is very important to include in your decision making the methods and ease of maintenance on the product before buying one.

-How easy is it to empty and clean the collection cup? This is a daily task and collection cup design is a very important factor.

-How easy is it to get into the skimmer with your arm for scrubbing the walls? You won't be cleaning the walls except maybe every 6 months to annually.

-How easy is it to clean the bubble creation device? Can you easily get to it with a small bottle brush?

Cleaning the collection cup should be done daily for optimum performance. As residue builds up on the neck of the cup it can impede the rising of the foam and ultimately the amount of gunk that you remove from the system.

To Skim Wet or Dry?

Another thing to consider is whether you want to skim wet or skim dry? Skimming wet is simply lowering the collection cup and/or increasing the air flow so that it removes more skimmate albeit less dense and lighter colored organics from the system. Skimming dry is raising the collection cup and removing only the nastiest stuff from the system. Skimming wet means more freshwater water top-offs, more salinity checks with the refractometer and possibly testing more often for depleted iodine levels. Skimmer dry means less water top-offs but possibly more dissolved organics left in the system.

There are even those hobbyists out there that utilize wet skimming as a part of their water change schedule. Skimming wet lets them remove the most dissolved organics and as they are monitoring their salinity levels they may notice that it will start to drop as they skim wet. When doing water top-offs you will want to make up for the lost salinity by using pre-mixed and aged saltwater to make up for what was lost via the wet skimming. A bonus to skimming wet is that the neck doesn't accumulate as much protein gunk around the inside of the neck on the collection cup, so a little bit less maintenance on a day to day basis.

The decision is totally up to the aquarist. Only you know how well your skimmer works on your particular system and you know your own maintenance habits. Some find a good middle ground between wet and dry skimming. There is no right answer here that covers all situations.

Parting Thoughts...

Protein skimmers can be a valuable asset for your saltwater aquarium. They can help create a more stable environment for your animals and a healthier one too. If you just can't afford a decent protein skimmer you should honestly rethink the whole saltwater thing, at least for now. Especially for a beginner to the hobby our goal here is to make sure you have all the tools you need to succeed while having fun. Save up enough money until you can afford one a later date. You will be glad you did.

One last thing, protein skimmers are very expensive and the old saying that "you get what you pay for" certainly has some merit with skimmers. Trying to go the inexpensive route will often end up costing you more in the long run. I've been there and done that. Don't waste your money on a cheap skimmer. This piece of aquarium equipment is just too important. Get a good one from the start after researching them thoroughly.

Thanks for reading.

By : Mike FishLore


Add Your Tips or Comments!

Protein Skimmer Reviews

Octopus 800s Protein Skimmer - *Very good skimmer
Octopus 200 NW Protein Skimmer Review - *Very good skimmer
AquaC Remora Protein Skimmer - *Very good
Tunze Nano Protein Skimmer - *Very good
Hydor Slim Skim Protein Skimmer - *Ok skimmer
Red Sea Prizm Protein Skimmer - *Ok, needs frequent adjustments
Fission Nano Protein Skimmer - *Don't waste your money
Visi-Jet-PS Protein Skimmer - *Don't waste your money


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