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Q10751 - INFO: Reef Ramblings—All About Skimmers by Adam Blundell M.S.
What Is A Protein Skimmer?
A protein skimmer is a mechanical device that helps to remove organics from the water. Home aquariums are often very high in organic levels. Much, much higher than you would find on a natural reef. One way to help remove organics is by protein skimming. In fact, second only to water changes, I can’t think of a better way to remove organics. Here is how it works: Water is pumped from your aquarium into a big tube and from the tube back into your aquarium. Of course, inside the tube is where the magic happens. A large amount of air is mixed into the water column creating millions of tiny bubbles. These little air bubbles "stick" to the organics in the water and, as the air bubbles rise, they carry the organics with them. This produces foam, which is collected and thrown away. The process is exactly like you see when waves crash on shore and foam is washed onto the beach.

Who Needs a Protein Skimmer?
A protein skimmer is not for everyone. However, it is almost always helpful even for those who do not necessarily need one. The best thing you can do is to analyze your system and see if you are currently providing enough filtration for your specific animals. In reef aquaria, this is almost impossible without a skimmer. Simply put, skimmers are a staple in reef aquaria.

Let’s assume you have a 125 gallon aquarium with 50 pounds of live rock. Let’s also assume you have 3 small fishes. With a healthy refugium and small feedings every couple days, this aquarium will probably run hassle free for years without a skimmer. Now let’s assume you have a 30 gallon aquarium with 4 tangs, 2 angels, 2 anemonefish, and 3 wrasses. You may feed this aquarium daily. This aquarium would almost certainly be better with a skimmer. In fact, it would be irresponsible of me to suggest otherwise.

For very large aquariums it is recommended that you have a very large skimmer. These skimmers often require a separate space since they probably won’t fit inside the stand or sump area.
Copyright Blundell.
For very large aquariums it is recommended that you have a very large skimmer. These skimmers often require a separate space since they probably won’t fit inside the stand or sump area.
Skimmers can be adjusted for how wet or dry they run, which means how high up the water level is in the skimmer chamber. You can adjust how easily they bubble up and remove waste particles.
Copyright Blundell.
Skimmers can be adjusted for how "wet" or "dry" they run, which means how high up the water level is in the skimmer chamber. You can adjust how easily they "bubble up" and remove waste particles.
Your Skimmer Needs
This is the tough part. If we stick with our previous example on the 125 gallon few fish vs. the 30 gallon with many fish we can instantly see a difference in bioload. Now let’s add another factor to that example. If the 30 gallon aquarium is intended to just house fishes with some live rock, then an "average" skimmer may do fine. If the 125 gallon tank is intended to house many small polyp stony corals then it may need a very large skimmer, even though it doesn’t have many fishes.

Did you get that? AQUARIUM SIZE IS IMPORTANT, BUT SO ARE THE REQUIREMENTS OF THE LIVESTOCK. Therefore you can’t easily rate a skimmer for a tank size. This is frustrating for many hobbyists. I get phone calls from people asking "Adam, I have a 180 gallon tank. What skimmer should I buy?" I have no idea how to answer that. Do they have a lot of rock? Do they have many fishes? Are they keeping corals? How often do they feed the tank?

Selecting a Skimmer
As a way of helping hobbyists select a skimmer, most manufacturers rate their skimmers for tank size. Again, this is difficult to do, so they make some assumptions and do the best they can. If a company is selling a skimmer and it is rated for a 120-150 gallon aquarium, they are assuming you actually have a tank that size with a few fish, some corals, a clam or two and feeding once each day. Some skimmers come with multiple ratings. The company will say something like "good for 100 gallons of fish only, 75 gallon reef aquarium and 50 gallon small polyp stony corals." No matter how the company rates their skimmers, you still need to consider how your tank compares to the rating system.

Take a look at your system. Do you have a sump area to hold a skimmer? Will you need a skimmer that hangs on the back of the aquarium? Do you have a separate fish room with all your equipment that could house a large skimmer? Start with some of those basic tank design questions. Your answers will help narrow down your choices for skimmer brand and design.

Now you can look at how large of a skimmer to purchase. The general rule is buy as big as you can. But again, this is a great opportunity to ask yourself how much food you are putting into the aquarium, how many fish you have, what other filters you have running and all those sorts of things.

Some people like to house their skimmer external from their aquarium.  They often cover the skimmer with cabinets, which have been removed to take this picture.
Copyright Blundell.
Some people like to house their skimmer external from their aquarium. They often cover the skimmer with cabinets, which have been removed to take this picture.
A skimmer provides visual evidence of its work. Unlike the process of liverock breaking down waste, you can see exactly how much your skimmer is doing. It is important to frequently clean out the collection cup and the neck that leads to the cup. This greatly enhances skimmer performance.
Copyright Blundell.
A skimmer provides visual evidence of its work. Unlike the process of liverock breaking down waste, you can see exactly how much your skimmer is doing. It is important to frequently clean out the collection cup and the neck that leads to the cup. This greatly enhances skimmer performance.
Conclusion
A few final thoughts. Home aquariums have far higher nutrient levels than wild reefs. So there isn’t much fear in over-skimming. Second, you can easily add more food, but you can’t easily remove more waste. So if your tank is "too clean," that is very easy to fix. What is a real nightmare is when your tank is just too dirty. And a final third point I want to leave with you is the idea of catastrophe. There will indeed be a time when you will lose a very large soft coral. When something like this happens it would be great if we could just turn on an extra 5 skimmers. So while your skimmer may be able to handle the daily filtration of your aquarium, it may not be able to handle a large problematic day. This is yet one more reason to have an oversized skimmer to help in those rare, catastrophic days.

Author Information
Adam Blundell M.S. is a hobbyist, lecturer, author, teacher, and research biologist. Adam is the director of the Aquatic & Terrestrial Research Team, a group which bridges the gap between hobbyists and scientists. Adam can be reached by email at adamblundell@hotmail.com.
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Approved Comments...
something is beter then nothing Approved: 4/23/2010
Good article. I would like to add something I have learned over the years. Venturi valve skimmers get clogged quickly < 1 week. Skimmers with small parts are VERY difficult to clean and require more frequent attention. Without promoting any specific brands, stick to the ones that have a large collection cup, easy to disassemble, and have a neck that you can reach into with your hand. Better yet, make one yourself... Approved: 10/22/2008
I wish I read an article similar to this one when I entered the hobby. The initial expense of getting a larger, more capable skimmer seems to high if all the benefits are not considered. My second skimmer is certainly more capable, and had I not wasted money on the first one, it could have purchased even larger. Approved: 10/14/2008
info on equipment use is allways good Approved: 10/6/2008
I rated this content excellent because you cant stress the inportance of a good protein skimmer. Approved: 10/6/2008
good info on why to have a skimmer Approved: 10/4/2008
very detailed and easy to understand,,I now wish I had read this before I purchased my skimmer, however I think the one I purchased will be sufficient for now,as I do not have any fish in tank as of yet,,only live rock, one coral, one blood shrimp,... Approved: 10/4/2008
Sharing information such as the size of the skimmer is not just dependent on the size of the tank but what is in it, including corals. I never would have thought about that. Approved: 10/4/2008
This is the first honest appraisal of skimmers I have seen Approved: 10/4/2008
I was wondering what a protein skimmer was and how it worked, and also why I would need one Approved: 10/4/2008
the article was good but needed - pros and cons for different types of skimmers and the fact that diff styles remove at diff rates and maybe some info on the benificial nutriant loss do to skimming and the additives that can counter act this ... all in all the info it had was very good Approved: 10/4/2008
Nothing said as to use with Fresh Water Tanks;Not Necessary?Should be considered? Approved: 10/4/2008
Great intro. Please follow-up with different models and a better description of skimmer capacity. Measuring the nitrates, etc. in your tank help i.d. bioload and effectiveness of a specific model for a tank setup. Thanks, Bob Approved: 10/4/2008
Great overview on need for a skimmer for a Reef Tank and the need to put as large a skimmer as you can fit. Approved: 10/4/2008
Very well written, good coverage of material. Becket and needle-wheel options may be good info to add eventually. Thanks Approved: 10/4/2008
It answered many questions I had about protien skimmers. Thanks. Approved: 10/4/2008
THE BIGGEST PROBLEM I HAVE WITH THIS ARTICLE IS THAT IT SUGGESTS THAT A SKIMMER IS NOT FOR EVERYONE. IT ABSOLUTELY IS FOR EVERYONE, ESPECIALLY IF YOURE A BEGINNER. SURE, 15 - 20 YEARS AGO THEY WERE SIMPLY AN OPTIONAL ACCESSORY, BUT NOW THAT WE KNOW WHAT WE KNOW, THERE SHOULD BE ABSOLUTELY NO HESITATION IF SOMEONE IS OFFERING ADVICE, WRITING AN ARTICLE, OR A SALESPERSON HELPING A CONSUMER, AND THAT IS A SKIMMER SHOULD BE A STANDARD PIECE OF EQUIPMENT IN ANY SALTWATER APPLICATION. OF COURSE, YOU CAN GET AWAY WITHOUT USING ONE (WHICH SHOULD BE LEFT TO MORE EXPERIENCED HOBBYIST WHO CHOOSE TO DO SO), BUT THE POINT SHOULD BE HAMMERED HOME THAT THIS MECHANICAL DEVICE IS INVALUABLE FOR WHAT IT DOES AND THAT ESSENTIALLY NOTHING ELSE CAN ACCOMPLISH. ITS WORKING 24/7/365 AT REMOVING POLLUTANTS FROM THE AQUARIUM WHICH IS BEING PRODUCED ON A DAILY, IF NOT,HOURLY BASIS. WATER CHANGES, CARBON, AND OTHER CHEMICAL MEDIA JUST CANT KEEP UP WITH THAT TYPE OF PERFORMANCE. SUGGESTING A SKIMMER IS SE Approved: 10/4/2008
this article has many good points to it. makes a person think about additional items to consider in theory and applicable uses. Approved: 10/3/2008
No self respecting aquarist would put three tangs in a 30 gallon let alone one, I appreciate the point you are trying to make but man Some new reefers may think that is ok, bump up the amount of fish in the tank to make a point rather than add fish that would die due to the stress of such a small tank. Sorry just playing my part as a tang cop :) Approved: 10/3/2008
Very informative breakdown of skimmer requirements and answered my question of "Is my skimmer big enough or too big". Thanks! Approved: 10/3/2008
Maybe add an additional skimmers as well, like 2 smaller are better than one large one.One fails the other will keep... Approved: 10/3/2008
Article Details
Created on 9/30/2008.
Last Modified on 10/7/2008.
Last Modified by Keith MacNeil.
Article has been viewed 7480 times.
Rated 9 out of 10 based on 61 votes.
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