What does a protein skimmer do?

Protein skimming (foam fractionation) is actually another type of filtration.

[tag-tec]Protein skimming[/tag-tec] allows for the removal of certain types of DOC’s ([tag-ice]dissolved organic compounds[/tag-ice]) from the water. What happens is that very small bubbles of air are passed through the salt water – this occurs inside what is normally called a reaction chamber. The organic matter in the water ‘sticks’ to the side of the air bubble and rises up with the bubble. Once the bubble reaches the top of the chamber foam is created. Over time these organics get pushed higher and higher until eventually they rise and fall into the collection cup of the skimmer ready for emptying by the aquarist. [Read more]

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11 Comments
  1. Your website is proving invaluable as we set up our first marine aquarium. It is not only full of information but is easy to read and understand too. Thank you!

  2. Thank you for the compliment and I am glad you are finding it useful.

  3. Hi, your webasite is useful as I was thinking of running my protein skimmer part time as my leather toadstool seems so be on its way out, and I fear that my skimmer is taking all the nutrients out the water, I have only just started to add calcium and magnesium as I did not think it was important for one coral!! thank you!

  4. We’re always pleased that the website is helpful and of use.
    It is known that corals are able to take in nutrients from the surrounding seawater, which includes dissolved organics. I don’t know if all corals can do this, but many can. Thus some aquarists are running their protein skimmers part time, using electrical timers to control them.
    My protein skimmer is not known to be highly efficient, and in earlier days I considered changing it for a known more efficient model. However, on reflection I realised that ‘the proof of the pudding is in the eating’. My soft coral reef is doing well and has done in its 5+ years of existence. I do not directly feed the corals, though some do get food targeted at the fish. Maybe they use dissolved organics? If I started skimming more efficiently, maybe I’d upset the balance……
    It is still the case, in my opinion, that beginner/novice aquarists should continue to use an efficient skimmer fulltime.

  5. Hi thanks for the reply to my previous comment expert advise is always appreciated from a beginner, all beginners will say that!!. Back to the skimmer I am using a V2 600 with a jewel 180 with about 18kg of live rock, so I figure there is about 150 litres in there, and I have added an adjustable inlet valve on it for the air intake mainly to make it quieter and also because it is very powerful so not to overskim….. So reading your reply to my comment I figure that I should maybe run it full time ❓ . My livestock is a Yellow Tang, Regal Tang, 2 Clownfish and a Mural Goby, If this makes any difference to the skimming? I figure that this is enough livestock for this size tank, although its tempting to add more!!. Thank you once again :mrgreen:

  6. I feel more secure when a beginner uses a skimmer in the first place! I also feel better when it is running full time.
    Perhaps the best way forward is to run the skimmer full time and observe. The skimmer will take out a lot of organics before this can be converted by the bio-filter, which means, in theory anyway, less nitrate,
    Skimmers also (like activated carbon), take out desirable seawater ingredients such as trace elements. Routine water changes should deal with this.
    A skimmer should be regularly cleaned (the throat area, where the gunge builds up, also the cup) or efficiency will reduce.
    When experience builds up confidence, pehaps a careful experiment with reducing the skimmer bit by bit from 24 hours…..

    Enjoy your aquarium.

  7. hi there i have just bought a marine fish tank i am new at this so forgive me if i sound stupid my tank is a aqua one where the back of the tank is separated for the equipment to go in the back out of sight the system works on a refugium i was stuck when i got to the skimmer i bought a r.o man reverse osmosis unit to produce pure water i have filled the tank not added my salt yet but got every thing running in the back is the skimmer supost to bubble and if so should it bubble near the top of the neck or at the bottom thanks trying to do everything right

  8. The skimmer should bubble, and bubble a lot. The whole cylinder should be filled with bubbles. Sometimes an air hose becomes clogged and it stops the air from entering to create the bubbles.

    Ok now this is the tricky part, and you will find yourself adjusting the water level a lot on most skimmers. But you want to start the water level low and slowly bring it up. Overtime the skimmer will create a foam that will pop and pour over into your collection cup.

  9. thanks for that should i test the water before i add the salt even thoght i used a reverse osmosis unit or what should i do thanks

  10. i just put all the water in the tank and then i was going to add the salt i added 180l of water what it said in the manual what the tank held have i done right doing it that way

  11. Hi,

    As previously said the entire reaction chamber should be full of bubbles and should look ‘milky’.

    Personally I always test reverse osmosis water every once in a while primarily for nitrates and phosphate to ensure that I am not putting these into the aquarium directly with the water.

    Regarding adding the salt you have done it the correct way in adding the water first. Add the water and then bring it up to the correct temperature. Once it is heated up add the relevant amount of salt and turn on the pumps. There is no need to run the skimmer at this point as there is nothing in the aquarium for it to remove. Leave the aquarium overnight and then test the specific gravity. If it is low then add more salt. If it is high then add more water. Once it is correct you can then get cracking with the filtration.

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