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Q11085 - HOWTO: How to Setup a Media Reactor by Keith MacNeil, Reef Squad

To maintain pristine water quality in our aquariums, hobbyists often utilize carbon, ferric oxide media (like ROWAphos and Phosban) and/or other filter media to absorb dissolved organics and other chemicals from the water.

There are many ways you can add media to your aquarium. One of the best ways is by using a fluidized bed filter (FBF). Fluidized bed filters are commonly referred to as phosphate or media reactors.

Perhaps you've been wondering what a media reactor is and how they work. This article is for you.

They say a picture is worth a thousand words. To save you some serious reading, I've included an up-close photograph of Two Little Fishies Phosban Reactor 150.

Two Little Fishies Phosban Reactor 150 Two Little Fishies Phosban Reactor 150: Inlet & Outlet
You'll notice two hose barb fittings at the top of the reactor, these are the inlet and an outlet. Water is pumped into the media reactors inlet through flexible tubing attached to a small powerhead. The inlet is connected to a center tube that carries water down to the bottom of the reactor. Water then flows upward through the media—allowing it to move and become "fluid"—before exiting through the outlet.

Seems simple enough, right? Good, because it really is that easy. The advantages of these filters are that they are not only effective, but easy to setup and maintain.

If you're wondering why using a fluidized filter might be better than simply placing a filter media bag inside a canister or other like-minded filter, we have the answer.

Water travels the path of least resistance when flowing through a filter. As detritus inevitably begins to clog the media within a canister filter, the water will start "channeling" around the clogged area(s) and only come into contact with a portion of the filter media. The media inside a fluidized bed filter, on the other hand, is constantly churned within the reactor. This prevents channeling and allows greater contact time between the water and filter media.

The items you'll need to setup your own media reactor include:
  1. A media reactor
  2. Filter media
    Carbon and phosphate media are among the most popular varieties.
  3. Powerhead/Water Pump
    Your media reactor may include a pump. Be sure to read the product description carefully before buying to determine if you'll need to purchase one separately. If your reactor does not include a ball valve to adjust water flow, I recommend purchasing a feed pump with adjustable flow so you can dial in the proper flow rate.
  4. Flexible tubing and hose clamps
For my setup demonstration, I am using Two Little Fishies Phosban Reactor 150, Aquarium Systems Mini Jet 606 Powerhead and Two Little Fishies HydroCarbon2.

The first thing you'll need to do is decide where you will place your reactor. I am hanging the reactor in this demonstration on the side of a sump.

Reactor Hanging on the Sump Reactor with Tubing and Pump Connected
Next up: find a suitable location for your feed pump. Once you've chosen a spot, cut an appropriate length of tubing to connect the pump to the reactor. Remember to measure twice, cut once. You may also cut a piece of tubing for your exit line.

Since I've decided to place the pump in the bottom of my sump, I will cut 1 ½ to 2 feet of tubing to connect the pump to the reactor. The TLF Phosban Reactor I'm using includes a ball valve I will add between the pump and the filter. The instructions included with the reactor mention this, so I will reiterate: do not restrict the flow exiting the reactor. The pressure that builds up can cause leaks.

If the products you're using to setup your media reactor are new, you may want to give them a good rinse at this point to remove any dust, glue or residual debris that may have settled during the manufacturing process.

Rinse your filter media as well, per manufacturer guidelines. Instructions may differ slightly from manufacturer to manufacturer; free to contact us if you have questions.

It's time to add carbon to the reactor. But before you can place the media inside, you'll need to remove the top plate/sponge. Plug or cap the center tube— a piece of tape will suffice—to prevent media from falling down it. I actually used a strainer from an old Maxi-Jet Powerhead.

Fill the reactor chamber halfway with carbon. You really can't overdue it with carbon, so don't worry about adding an exact amount. Personally, I'd rather have too much carbon than too little. However, when I use phosphate media, I always adhere to the manufacturer's recommendations.

Adding Carbon to the Reactor Reactor Half Full with Carbon Media
After filling the reactor chamber halfway with carbon, remove the cap you placed on the center tube and replace the top plate/sponge and fasten the lid.

Place or hang the feed pump inside your sump with the tubing attached. Then connect the tubing to your reactor. The outlet drain line will also need to feed back into the sump (or tank). I try to pull water from one side of the sump (where the water enters the sump from the tank) and drain it near the systems main return pump.

Assembled Reactor Reactor Ready to Go
You are ready to turn the pump on. There may be some dust leftover even after rinsing the media, but this isn't a big cause for concern. Just slow the flow down after plugging the pump in to limit dust and media from entering your aquarium.

Once the water inside the reactor has cleared, you can fine-tune the water flow inside the chamber. Ideally you'll want to see a bubbling or boiling-type action at the top section of the media.

Congratulations! You have successfully setup a media reactor.

Fluidized Reactor in Action

"Can I mix different types of media within the same reactor?"

This is one of the most common questions aquarium hobbyists have about media reactors so I felt I should share my opinion on the subject.

I believe you are better off running multiple reactors than mixing different types of filter media together in the same reactor. You may alternate media types—running one type for a month and then switching to another.

The reason I don't think media types should be mixed within a single reactor is because each type of media requires a different flow rate to maintain fluidization inside the filter.

Carbon usually requires a higher flow rate than phosphate media. If you run the filter with a slower flow rate for phosphate, you risk having carbon media settle at the bottom. This can cause channeling. If you set the flow rate higher to keep the carbon fluidized, you risk pushing the phosphate media right out of the reactor.

Also, depending on your waters chemistry, you may find the time between changing different media varies. For example, your carbon may need to be replaced every 2-4 weeks whereas your phosphate media may not need to be changed for 6-8 weeks.

Risks aside, it is doable. Bear in mind you'll need to carefully observe your media and flow rate to prevent the aforementioned problems.

Another frequently asked question: "Are all media types safe to use inside a media reactor?"

The answer is, unfortunately, no. Some types of filter media just don't do well in the fluidized environment. Fluidizing some types of media will cause them to break down and crumble into a fine dust. Other types are either too large or too small. When in doubt, give us a shout! We'll be happy to let you know if the media you have in mind is suitable for a fluidized bed filter.

Media reactors are fairly simple pieces of equipment that can dramatically improve the water quality of your aquarium. Whether you run carbon, phosphate or another type of media, as long as you follow best practices, you should begin to see improved water quality and clarity in no time.

Author's Note (9/18/10): It has been mentioned in some of the reviews of the article that carbon should not be fluidized as it can breakdown and cause a dust that possibly leads to HLLE and/or lateral line errosion. I was not able to find any proof of this in my search's of the internet (please contact me via the MD forums, username argi if you can help me find this).

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Approved Comments...
Told me all things I was not sure about e.g. Flow rates and mixing or not mixing media in the reactor excellent article Approved: 2/21/2015
Great article. It answered many questions I have. As a newbie I have a lot to learn. Approved: 1/22/2015
I just started to use a media reactor so this was very helpful Approved: 4/8/2014
Solid practical information Approved: 12/24/2012
Very easy to understand the information above and too helpful thank you so much to Marine Depot!:) Approved: 2/20/2012
I have been running 2 PhosBan 150 reactors for a while now. One with Bio-pellets and the other with carbon. I had to upgrade to a inexpensive ($60 range) submersible pump that I was able to plum with a "tee" to go seperately to each reactor. Have each one with its own ball valve (included) to control seperate flow rates. Filled carbon reactor to the top and run it wide open (not being tumpled cuz its filled to the brim) filled the other half full with bio pellets to hopefully help reduce phosphate and nitrates in my tank. Works like a charm! No leaks. Pleanty of flow. Easy, quiet, convenient. Approved: 1/23/2012
Great information. Approved: 8/8/2011
I am using bags with my media. wrong, thanks Approved: 5/25/2011
Good overall amount of information and solid approach. I would also add (from my experience) when flow thru the phosphate reactor cannot be regulated (due to setup) a fine filter mesh can be attached at the output pipe of the reactor to catch any particles of phosphate media coming thru (I use RowaPhos and get a tablespoon of particles every month). Approved: 2/27/2011
Good article, seeing as you asked Id offer the following. Once the media is washed and you are running up for the first time. I would recommend that the pump and return pipe are put into a bucket of old tank water before being turned on. This will limit the damage if there is large amounts of dust. Also how about adding a chapter about reactor flow adjustment / testing the output and the decision when to replace the media. Approved: 1/2/2011
I have been running the Phosban 150s with Maxijet 400s on several tanks for a year + now with outstanding results and want to run them with Carbon as well. Question i have is: Would it be wise to put the Carbon reactors in line prior to the Phosban reactors with the single Maxijet 400 running both. Since the flow rate may be diminished somewhat, i am hoping the flow rate will work nicely without stepping up to a Maxijet 600. I restrict the 400 a bit as it is with just the Phosban reactor, and feel that the carbon may not need to "tumble" anyways, reducing the crumbling issue. Thanks and looking forward to your advise. (editors reply: Yes that should be fine to run that way). Approved: 9/22/2010
Your article is a fine work. Approved: 9/20/2010
Good article - would be good to get advice re pumps. I have added a tap in my flexible tubing as a feed from my return pump to control flow to deltec reactor. Can you add BIO-BALLS to a Phosphate reactor? Approved: 9/20/2010
Should give an example of which pumps can run dual reactor situations for more advanced set ups. Ive seen people running dual 150 reactors with a MaxiJet 600 with good results. But how would one do this with two different media types? I know GFO comes before Carbon due to the slower flow rates recommended for GFO. Otherwise it is a good basic reactor set up primer for anyone who is interested in setting up a single reactor. Approved: 9/19/2010
Im going to try it. Approved: 9/19/2010
I think if you adjust the flow rate of the pump with carbon just below the flow rate for fluidise the carbon, you have a speed of water enough for not have "channeling". Approved: 9/19/2010
Recently lost several mature corals. Our loal suppliers said we should consider a phosphate reactor. Timely article. Thank you Approved: 9/18/2010
I havent gotten this advanced yet so, all of this information was extremely helpful, thanks from a visual person :) I have maintained my 24 gallon aqua pod for 1 year now and I am getting ready to set up my 75 gallon with 2 HOB 280 Marine Land filters. Do you think I will need to set up a media reactor too? Please keep going with the simple education articles. Laurie in Florida (editors note: Laurie please email us at for assistance) Approved: 9/18/2010
Im Happy With the explanation Approved: 9/18/2010
Short articals that are to the point are invaluable. Althought I have been using this setup for over a year now it was a great refresher and I learned a couple thing I didnt know. Thanks for the great tips. -Gerry Harrington Port Saint Lucie, Fl Approved: 9/18/2010
I thought it was never a good idea to fluidise carbon as it will break up. Most reactors Ive seen for carbon have the carbon stationary. GFO on the other hand different. Approved: 9/18/2010
Great instructions. Clear and concise.. Thanks! Approved: 9/18/2010
Excellent article. It would be nice to also list media that you carry thast performs well in a fluidized bed filter. Keep up the great work. Approved: 9/18/2010
Well explained. Its a lot simpler than I thought. Approved: 9/18/2010
Iam fighting with an over abundance of micro algae. Im using a phosphate media, but after reading your article, it strikes me that I can optimize the effectiveness of the media with this mechanisn Approved: 9/18/2010
Thanks! Very clear and concise. Approved: 9/18/2010
You should never tumble carbon as the fines produced from the carbon rubbing and breaking down have been proven to contribute to lateral line and hole in the head diseases by a scientific study, not just anectodtal evidence. Approved: 9/18/2010
Simple and to the point. Condensed version of what I have heard explained a hundred different ways. Approved: 9/18/2010
I did not think that carbon should be fluidized since it will crumble and create fines. Also I find that ferric oxide seems to stack at the top of the reactor. even with a slow flow rate I cant seem to keep it moving. Approved: 9/18/2010
I use one of these reactors and love it-- simple set up and easy to use! Approved: 9/18/2010
Clear and understandable article. Approved: 9/18/2010
Did what it said on the box! Id always wondered what fluidised meant, what media meant and reactor meant. Especially when used in the same phrase. Now I know. Very good andf clear description Approved: 9/18/2010
Very clear and good sample pixs. Thanks. Approved: 9/18/2010
Article Details
Created on 9/15/2010.
Last Modified on 2/7/2012.
Last Modified by Dot Yuson.
Article has been viewed 36736 times.
Rated 8 out of 10 based on 142 votes.
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