A skimmer is a tank water filtration device.  Water and air are mixed by a pump in the lower part of a vertical chamber producing bubbles.  Pollutants are trapped on the bubbles due to the hydrophobic effect and are pushed up the chamber on top of each other until the bubbles spill over the top into a collection cup that rests on top.  The collection cup is then cleaned as needed and placed back on top.







The natural skimming effect of the ocean


LifeReef says…

Needle-Wheels: Can be noisy due to vibration and rigid mounting to skimmer body. Can be more noisy due to air cavitation since the air is introduced before the pump, and the pump needle-wheel beats the air into bubbles. Less friendly to plankton and copepods since the needle-wheel acts like a blender, unlike standard pump impellers that simply move “pockets” of water through the pump, something to think about if using a refugium. And something else to consider is the proprietary pump which means no other pump can be used on this type of skimmer. Lifereef skimmers can use any pump as long as the minimum gph is maintained.

Becketts Venturis: The Becketts is nothing more than a big venturi. It must be housed in its own chamber to prevent water from spraying all over and stop the loud sucking noise, add another air valve to fiddle with and you now have three adjustments you have to get in harmony: water in, air in, water out. And if you tweak one you have to tweak the others. The Lifereef skimmers have only one adjustment, a gate valve. Nozzle Injection: Think of putting your thumb over the end of a garden hose and spraying water into a bucket, that’s how nozzle injection skimmers work. Problems: the nozzle gets caked with salt requiring you to clean it (some even include a special cleaning tool) and a port on the nozzle so you can clean the salt, noise due to the high-velocity water hitting the surface of the water in the skimmer, very narrow adjustment range as the nozzle is either submersed or too far away from the nozzle to generate the microbubbles. Black box at bottom keeps you from seeing the water level needed for proper operation.

Conventional Venturis: These are any other venturi skimmer on the market and not the Lifereef venturis: Problems: Constant salt clogging which causes erratic skimmer performance and constant cleaning of the venturi. Noise, due to the venturi orifice sucking in air it makes a whistling or a sucking noise. Collection cup flooding due to erratic performance, due to venturi clogging, your cup can overflow. The Lifereef skimmers utilize a self-cleaning venturi which means your skimmer will perform more consistent, SILENT, never need the venturi cleaned of salt, and no collection cup flooding.

Now here is a very misunderstood area in design, function, and problems. The majority of downdraft designs can be identified by a closed box (or wet box) at the bottom of the skimmer and a large diameter uplift or “dry” column, and a water/air delivery of many different types. These skimmers may utilize for their air delivery a special spray nozzle, a Becketts venturi, a regular nozzle with a bio-ball column to break up the water stream into bubbles, or even a standard venturi with a larger water throughput. Problems, lots: Noise due to high-speed air being ingested into the column or shot onto the waters surface or onto the bio-balls. This design is difficult to trap and retain all the microbubbles in such a short closed box. Larger diameter uplift column requires a much stronger (gph) water pump, more water must be processed because the uplift columns are so short that contact time is reduced, and these types of skimmers REQUIRE a weekly take-down to clean the uplift column of sludge or the skimmer won’t work. And one last but very important issue: Skimmer sensitivity……. This means that these types of skimmers are extremely sensitive to water quality and air quality. You would think that you would want a skimmer that is sensitive to water quality but you don’t because these skimmers are actually working less time compared to venturi types. The reason is that because these skimmers are processing so much water, along with large volumes of air, that any minor water quality change will cause the skimmer to STOP FOAMING. A good example is when you put your hand in the aquarium or sump, and who hasn’t done that at least once a day. This minor activity will change the water surface tension just enough (due to body oil) that these skimmers will STOP FOAMING for hours, and sometimes days, before they resume “normal” skimming. And there are many other products that the average hobbyist adds to the aquarium water that can make these skimmers either stop working, or, foam so much that they can’t be run for awhile. And air quality? Being that these skimmers injest large volumes of air means that if you are cooking anything greasy like bacon, steak, hamburgers, hotdogs, hashbrowns, etc. that this grease molecule will get sucked into the skimmer and cause it to STOP FOAMING! It may sound funny but lots of customers don’t even think of this and can’t figure out why their skimmers aren’t working, neither can the manufacturer!

Note: We eventually removed the skimmer from our 180 KIS System.  We do employ a skimmer in our later 140 system.
You may not need one either depending on bio load, water change frequency, and other filtration methods.

A skimmer consumes electricity, creates heat, creates noise, and is a relatively expensive component.  Depending on how it is plumbed, a skimmer can be another potential water leak.

Does a skimmer strip good “stuff” along with the bad?