Skimz Monzter SM121 Internal Protein Skimmer

Skimz Monzter SM121 Internal Protein Skimmer
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Skimz Monzter SM121 Internal Protein Skimmer

55% Recommend this to a friend (6 of 11)

SKU: 208140

reg. $289.99

Special Price: $231.99

In Stock: 45
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Quick Overview

The Skimz Monzter E-Series SM121 Internal Protein Skimmer gives you high performance skimming at a great value. Bubble plate design minimizes pre-mature bubble bursting which also reduces height of the skimmer.

  • Rated for tanks 53 - 198 gallons (200-750 Liters)

  • BRS Recommended for tanks up to:

    • Heavy Bioload (Most Common) - 70 gallons

    • Medium Bioload - 90 gallons

    • Light Bioload - 120 gallons

  • Air intake: 143 GPH (540 LPH), making it capable of handling a higher water throughput.

  • Operating Depth: 7" to 9.5"

  • Low power consumption and high performance

  • Design allows cleaned water to exit bottom practically bubble-free

  • Skimmer draws water directly from sump

  • Features a Skimz ES2000 Needlewheel Pump - no feed pump required

Full Details

Skimz Manufacturer's Manual



  • Integrated cylindrical and cone shape chambers help reduce bubble bursting and surface agitation
  • Bubble Plate Design - reduces turbulence
  • Maximum air flow capacity in compact design
  • Micro-adjustable valve for precise water level control
  • Twist-lock neck for easy collection cup removal
  • Quality construction - CNC machined parts and Georg Fischer fittings
  • Internal application - no feed pump required


Skimmer Specifications:

  • Body Diameter: 4.72" (120mm)
  • Foot Print: 6.25” x 7”
  • Total Height: 21” (530mm)
  • Cup Diameter: 150 mm


ES2000 Needlewheel Pump Features:

  • Skimz worked with an Italian pump manufacturer, using advanced material for the needlewheel impeller, seamless-coated rare earth magnet for durability and high performance.
  • Air Draw: 143 GPH (540 LPH)
  • Power Consumption: 12 Watts


Skimz Warranty

  • Warranty for Original Purchaser against defective material and workmanship that occurs during normal use.
  • 2 Year Warranty on skimmer body
  • 1 Year Warranty on pump


11 Items

  • Lots of Problems By Jason on 7/17/2017

    Used for a little less than two years, when it works it is great. The issue is it has lots of problems and is not reliable. Plastic screw broke after about a year's use, which is disappointing since I have only took it apart a few times. For the cost of this skimmer, it really wasn't worth it. Do not buy.
  • Works properly overall, but has some annoying flaws By Greg on 6/5/2017

    Same theme as a few other reviews. The pump on this thing can be very loud at times, I dont know what causes it, but there are times where it can make a noticeably noise, if I turn the pump off, then turn it back it makes it go away until it decides to start again, which could be in an hour, or a week.

    I also hate the base of this thing, it just doesnt seem very sturdy at all. A nice big square platform for the pump and the rest of the body to sit on would have been nice.
  • NOT WORTH THE HASSLE By Garrett on 5/11/2017

    Ive had this skimmer for almost 2 years now and never have been able to get it to be perfectly tuned. I'm running it on my 40g breeder, and I never can get a consistent skim to form in the cup. After about the first 6 months of owning the pump went bad and wasn't producing and bubbles, BUT BRS kept its word and honor its warranty very promptly, so BIG PROPS to the team at BRS! The skimmer is also very noisy, even after replacing the pump, when you close the air choke up it makes the pump very loud. I ended up purchasing a reef octopus skimmer instead because I am tired of constantly trying to get this skimmer working correctly.
  • Pump has bad design. By Sirduckingtoniii on 1/29/2017

    I had the skimmer for about a week while my tank was cycling and all was well. Then the pump started making an annoying noise like a car over revving it's engine if any air was allowed through the venturi. I messaged BRS and they swiftly sent a replacement pump. The pump was silent for a week before the exact same thing happened. Now i have to have the venturi almost completely closed otherwise it makes an annoying noise. I can only conclude that the pump has a design fault or something that causes this to happen. Would not recommend.
  • Fantastic Skimmer By Craig on 5/28/2016

    I love this protein skimmer! I have had it a little over one year. There is a learning curve to dialing in the settings, but I suppose that is with any skimmer. I have no regrets with the skimmer itself, but my pump on the skimmer has quit working. I cleaned it to make sure there was nothing blocking the input or output, but nothing. I know the pump is only guaranteed for 1 year but I would expect at least 2 years of use out of a single pump. I have a 75 gallon tank with a 40 gallon breeder as my sump. I have not been overworking the pump, so I am not sure what caused it to quit. For now I am left with the decision of replacing the pump with little confidence in ordering a Skimz brand pump. Please don't misunderstand my review, the skimmer is really great! The pump was powerful, but didn't seem to last long enough.
  • Great skimmer By Dave on 9/5/2015

    I replaced my cad lights pipeless skimmer with this Skimz skimmer and maaaan what a difference!! This skimmer rocks and adjustments are simple and easy! I will continue to purchase these skimmers for all my tanks. Thanks BRS for doing your homework & stocking these skimmers!
  • Green Sludge By Andrew on 2/2/2015

    Skimmer took about 3 days to fully break in and get tuned in for my 70g reef tank. My tank is lightly stocked with 2 clowns, 1 yellow goby clown and a wrasse and the usual clean up crew. Skimmer is emptied about once every 10 days and smells like it should with a hint of pepper. Had a minor problem with one of the pumps and Bulk Reef Supply sent out a replacement the same day of my call. The pump was having trouble starting up after cleaning and I did the usual trouble shooting methods. I would buy this skimmer again, it is well built, quiet and easy to clean and disassemble. The disassembly also works well in confined spaces like your sump as you can reassemble the skimmer in your sump. The skimmer was a bit loud for the first 3 days, but once broken in was very quiet. I can't hear it, even did a few tests of unplugging the skimmer, listened for a while, then plugged it back in. Bulk Reef Supply is my go to place for all my supplies, fast shipping and top notch customer service, you get real humans to communicate with.
  • Well-built piece of equipment but with a downside By Doc on 1/21/2015

    Well I waited a month before posting my review. The Skimz's skimmer is constructed very well. The only problem I have with the skimmer is getting it adjusted. It took me two weeks to get the adjustments just enough so that I am either not filling my tank with bubbles or finally getting it to fill the cup. The instructions are no help and getting it adjusted dis all on you. Don't know if I would recommend this to a friend because of all the trouble getting it adjusted.
  • love this skimmer By Ryan on 11/30/2014

    I've had the skimmer for a few months and have not had a single problem with it. The skimmer is well built and works great set up was not too complicated but took some time to get used to.
  • Good for wet skim only By Benji on 10/27/2014

    I purchased the Skimz SM121 for my 50 gallon cube reef tank. With the sump it has about 55 gallons water volume. The skimmer is built like a tank and really is a beautiful piece of equipment. I've owned the skimmer for 2 months and have went through hours of trying to adjust it correctly. I feel like the air valve adds a level of complexity and opens it up for more error. I've tried it with with every possible configuration possible but I can only get wet skim. Even though I have a heavily stocked aquarium I would only get 1/4 of the collection cup full with wet skim every week. Maybe it is just too oversized for a 50 gallon tank. I finally gave up after 2 months and switched to a Eshopps cone skimmer S 120 after seeing it in action at my lfs. After 24 hours the eshopps pulled out a dark skim mate with almost no adjustment. I really wanted to like the skimz but it did not work for me.
  • Great skimmer for the price By Joshua on 9/18/2014

    Great skimmer, takes a little bit of adjustment and time to set up, note that the instructions that come with the unit are not for this unit. Not incredibly difficult to operate but takes time and patience to get the water intake just right. But once everything is set it pulls out lots of nasty gunk from your tank which is great. The top screws right off so maintenance is quick and easy. High quality at a great price


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