Mr. Saltwater Tank

Carbon, GFO In A Saltwater Tank And The Easiest Way I’ve Found To Run Them Both

Carbon and GFO each have an important role in your saltwater tank and I’ve found a very easy way to run them both.

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Comments for this article (49)

  • Bob says:

    I have the same one on my tank, got to say LOVE IT! Very easy to change/clean.

  • Phil says:

    Mark, great video; but you forgot to tell when is the best time to change the media.

    they say for GFo is 0.003 ppm and carbon is the when the tank start going yellow. but i change my carbon same time as my GFO.

    thanx again Mark for another great video

  • Bryan says:

    Hey Mark
    Can you show me the difference between tumbling the GFO and grinding? I am running GFO and I am not sure if the flow is too much in the reactor or not.

  • David Rhode says:

    Mark–well done, i agree with you about this reactor. Since I have installed it my coral growth has gone wild and my water is crystal clear. I installed a valve off of the pump that supplies my UV filter. This way I have total control over the flow via gait valve.

    BRS has consistently provided some of the best supplies. They provide amazing support and speedy shipping.

  • Brice says:

    Great vid Mark!

    One questions though. What do you think is the best way to run GFO/ Carbon in a smaller nano-tank? Take for example your sexy tank 34g Solana….I’ve got a 34 and I don’t think I can run a BRS dual reactor (too big). What’s a good alternative?

  • Devin says:

    Hi Mark-
    I’m extremely glad you covered this topic! I bought my GFO reactor from BRS as well but they suggested I go with a single reactor for both due to the ease of cleaning them separately. I haven’t purchased the carbon reactor as of yet, I’m currently using Chemi pure elite bags but would like to move to the carbon reactor soon.

    My question is what is the difference between the two and does the reactor give better results?



  • The Berrier's Reef says:

    BULK REEF SUPPLY RULES!!!!! I love my reactor, its on a 30 gal, haha big reactor, small tank.

  • Adam says:

    Yes love mine. I think everyone should get one of these.

  • Marshall Harris says:

    Mark.. I have a question….. what do you think about UV Sterilizers and by the way thanks for all your tips and tricks….they really help

  • Adam says:

    I have wanted one of these for so long. I wish BRS shipped internationally.

  • Mad Hatter Reef says:

    Hey Mark… Not to shed light on my ADD,but what kind of Anthias is that in your tank? …Ooh, Look a kitty!

  • Robert says:

    Great video. Did not know about the clear cartridges. Will have to get a few on my next BRS order

  • saltwater tank boy says:

    Should i get a swc skimmer 150 or some reactors and lights. I have good lights but i think just need to upgrade. I was looking at the reactor because a BIG phosphate problem and i also have a moderate to large nitrate prob. thanks.

  • Giles says:


    Why do you say the carbon should not tumble. I run carbon and Roaphos (phosphate remover=GFO) in separate cartridges and make the Roa fluidise (i.e. as much movement as possible) and the carbon tumble to get water movement. Why do you think the carbon should not tumble?
    Good vids by the way. Enjoyed all the way in the UK 🙂


  • Harry says:

    Hi Mark can you still use carbon if you are carbon sourcing to keep the nitrates down. I one more question Dorso Syphon drains I have one on my tank can not seem to fine tune it noisy and guggling back ?

  • corocora says:

    Would there be a benefit to using GFO in a 12 gal. nano? I use ChemiPure bags now which do a good job keeping the water clear, just wondering if adding GFO would make it even better. If so is there a method for administering it to a nano compartment?

  • BobbyT says:

    Thanks for the Video Mark! I’m glad to see your still hard at work 🙂

  • Chris says:

    Wanting to know the difference between grinding and tumbling

  • Sylvek says:

    Hi where can i buy this in UK ?

  • sean says:

    Hi Mark
    Whery good Video with much praxis tips!!
    Hope to see more Videos like that
    Cheers from Switzerland

  • Sylvek…Bulk Reef Supply does not ship internationally. Come plan a trip to the USA and bring one back with you!

  • corocora…the GFO would help keep your phosphates under control if you had a phosphate issue. Since it is a 12g tank, your bioload might be so light that you don’t’ have any phosphates.

  • Harry…activated carbon and carbon sourcing are two different things so yes, I still use activated carbon

  • Giles…you don’t want the carbon to grind and create fines. Most activated carbons are very soft and even a tumble will make them grind and therefore create fines.

  • Jeff…Jeff…Jeff…look at the bright shiny object!! Hahaha… (Its a lyre tail anthers)

  • Brice…Two Little Fishies has a single hang on back reactor. It isn’t as user friendly as the BRS one but it works ok. And check out CPR Aquatics. They make small media reactors for nano tanks

  • Kevin says:

    Hey Mark, I was a little worried about getting the dual reactor because I wasn’t sure how to clean the media before putting it back on the tank. How do you clean the media (dust particles) before putting the canisters back on the unit?

  • Werner says:

    I cant find the Clear cartridge on the Bulk reef suppy website under GFO Reactors. Are you referring to the Bio Pellet Reactor cartridge?


  • Jimmy says:

    So with a GFO reactor do I ditch the cheeto? Seems like you can do both.

  • Simon says:

    Hey Mark,

    I love the GFO and carbon video…but you did not mention how much carbon and GFO you use in your tank or how you figured out how much GFO and carbon to use. Is there a calculation of grams to gallons or something? Let us know.

  • Wes says:

    Just rinse your media in a seive or filter sock with tap water, or better yet, tank waste water. A lot of people change media when they do their WC. The small contact time will not affect either media.

    Run Chaeto and your CS. Can’t hurt, but your macro may starve.

    BRS has a section that tells how much of their product to use based on size of tank.

  • miguel says:

    Hi mark,I got two little fishes reactor one w carbon and one w phosphate sponge , this I sponge works same like GFO . Or wats the difference.

  • Chris says:

    How do I know when to change the carbon and gfo, also say I double the recommended dose in the reactor, would this allow me to run the reactor about twice as long before I have to change media?

  • Pete says:

    I have a 90 gallon SW, just ordered the BRS dual reactor.. Have much carbon? How much GFO.

    Thanks for the great videos

  • Pete…BRS provides that calculator off their homepage. Just go to their homepage and click on the clownfish

  • JAXPete says:

    Got it, Thanks!
    Great videos — What main return pump are you running on your 90??

  • Pete…tunze 1073.05

  • lewy says:

    when you run the medias, do you wash them first or do you let the water flow through them to wash them out, and then run it into a bucket, if so won’t your water level drop in your tank

  • lewy…I rinse my media with tank water when I’m doing a water change. I let the water that has been run through the media pour into my water change bucket. That way I can throw it all away.

  • Jonathan Salcido says:

    Uh. Did you happen to notice the huge Black Clown assaulting that anemone???

    That clown is huge!

    Enjoyed this video, thanks Mark

  • Mike says:

    So I revisited this posting looking for some info. I have a 180 gallon tank (upgrading from my 90) I have the dual media reactor. I was wondering if I could run two dual reactors so I have two cartridges for carbon and two cartridges for gfo. I could use one reactor for carbon and one for gfo or I could run them with with carbon and gfo in a reactor. I am trying to find the best way to run enough media in my new tank because one dual reactor falls short of being able to do a 180


  • Mike…get a bigger reactor! running two chambers of GFO or Carbon won’t work too well as the flow will be too high for the first chamber and too low for the second chamber. Better to put all the same type of media in one reactor, and the other media in a separate reactor.

  • Brad Quigley says:

    Im looking at getting a single BRS reactor chamber would this be ok for 90 gallon tank. The people at BRS recommended I do that and tumble both carbon and GFO together and change every 2 weeks. Would this be ok. I have just a few algea spots in tank on live sand.

  • Brad…get the dual reactor. You’ll be much happier with it. GFO gets changed monthly, carbon every 2 weeks.

  • Travis says:

    I was just wondering what pump you are using for your BRS dual reactor. I have read some complaints online that the MJ1200 option they sell with it is not powerful enough to keep the GFO tumbling when the carbon is at the end of its life. Also how often do u change the filter pads on the carbon side?

  • Mike says:

    I am using the dual on my 180 still and I just change my media a little more often, no big deal.

    @Brad I would get the dual, I ran one on my 90 and was very happy, plus the cost is not too much more.

    @ Travis I use the mj1200 on my reactor and works just fine. Given the fact that you have to actually reduce the flow so it doesn’t totally just force your GFO into the the crabon side or tumble it too much. All you want the GFO to do is gently tumble. If you find that it is slowing down, just open the flow a little more.

  • Travis…I drove my media reactor off my return pump. Therefore I didn’t need a separate pump for just the media reactor. The MJ1200 will likely do a good job so long as the media reactor isn’t full or nearly full of media

  • Scott says:

    I have no sump but plumbed mine with 1/2 in silicon tubing to run sumpless under the tank stand

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