A protein skimmer removes the proteins and other organic wastes from the aquarium before they have a chance to break down into more harmful elements, such as ammonia and nitrite. Removing these wastes also helps prevent algae build-up, as does the reduction in phosphates. Protein skimmers are also helpful in removing any toxins released from corals or invertebrates in the aquarium. As a result of these effects, the water quality is therefore improved, and less frequent water changes are necessary. Protein skimmers have an added advantage in increasing the amount of oxygen in the water. Many saltwater aquariums could benefit greatly from having a skimmer.
The use of protein skimmers in reef aquariums is more controversial. In addition to removing phosphates, skimmers unfortunately, also remove trace elements which are necessary for corals and invertebrates. Natural food sources, such as plankton, are also be removed. If using a protein skimmer in a reef aquarium, these unwanted effects need to be taken into account. Some hobbyists will turn off the protein skimmer for 3-4 hours after adding phytoplankton.
Types of protein skimmers
There are 3 basic designs of skimmers:
- Counter Current
- Venturi
- Turbo
Each of the above skimmer designs can be efficient if used properly, but Venturi and Turbo are the more effective types. Effectiveness is based on the:
- Amount of bubbles produced (influenced by air flow rate)
- Size of bubbles (0.5 - 1 mm preferred)
- Contact time of bubbles with water
Counter Current: A Counter Current skimmer requires either an air pump, or an air pump and a water pump. The skimmer has separate water and air inputs. Usually, the airstone bubbles air into the bottom of the water column, while the water enters at the top. This creates a swirling, or vortex movement, which mixes the air and water. The height of the column determines the contact time of the bubbles with the water. Column height is often the factor that limits the use of counter current skimmers to smaller aquariums.
Venturi: A Venturi skimmer uses the Bernoulli principle of air injection, and relies on a good quality water pump. In a Venturi skimmer, the water pump is used to push water under high pressure through a component which has a narrowing in the middle. As the water exits the restriction, a pressure drop occurs, which sucks in air that is then mixed with the water. The higher the pressure of the water, the more air bubbles are produced. The water pump must be matched to the size of the skimmer.
Turbo: A Turbo skimmer draws air into the water intake of a water pump. There, impeller blades chop the air into tiny bubbles while mixing them with water. This creates a froth that is then forced into the skimmer chamber. Turbo protein skimmers may also be called "Needle Wheel" skimmers.
Protein skimmers may sound like the perfect filtration, and indeed they provide many benefits. But in choosing one, you will need to decide where your system will allow for its placement, how much work you are willing to put into it, how much money you want to spend, and whether you want to use an ozonizer.
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