# Fluval FX6 CO2 Reactor/Diffuser?



## Supa Mint (Jul 5, 2016)

I think that these have a 1" version: http://nilocg.com/co2-equiptment/

Good luck!


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## ScottW (Sep 17, 2016)

I was looking at the rex griggs reactors. I got a fx4 and eheim 2217 on my 60 gallon. Not to highjack your thread but will these reactors fit with ribbed hosing on the fx filters?


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## MaroMan (Jan 6, 2010)

I have an FX5 on my 75 gallon tank, I originally started with a Cerges reactor inline after the FX5. I wasn't able to get enough co2 to dissolve and already had a vertical tube taking the water from the top of the cabinet after it passed through the Cerges to the bottom of the cabinet which I just replaced with a homemade 3" Rex Griggs and I now have awesome diffusion of the co2, by the time the water gets back to my tank, there is almost no bubbles present but the water is saturated with co2. I would suggest making a Rex Griggs as I have seen really good results with these type of reactors!


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## ScottW (Sep 17, 2016)

MaroMan said:


> I have an FX5 on my 75 gallon tank, I originally started with a Cerges reactor inline after the FX5. I wasn't able to get enough co2 to dissolve and already had a vertical tube taking the water from the top of the cabinet after it passed through the Cerges to the bottom of the cabinet which I just replaced with a homemade 3" Rex Griggs and I now have awesome diffusion of the co2, by the time the water gets back to my tank, there is almost no bubbles present but the water is saturated with co2. I would suggest making a Rex Griggs as I have seen really good results with these type of reactors!


I thought about doing diy rex griggs reactor but couldn't find all the parts


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## Chadmanfoo (Jan 10, 2017)

MaroMan said:


> I have an FX5 on my 75 gallon tank, I originally started with a Cerges reactor inline after the FX5. I wasn't able to get enough co2 to dissolve and already had a vertical tube taking the water from the top of the cabinet after it passed through the Cerges to the bottom of the cabinet which I just replaced with a homemade 3" Rex Griggs and I now have awesome diffusion of the co2, by the time the water gets back to my tank, there is almost no bubbles present but the water is saturated with co2. I would suggest making a Rex Griggs as I have seen really good results with these type of reactors!


Thanks Maroman. I considered a Rex Griggs (perhaps 3" diam) but am having a really hard time sourcing the parts in the UK. What size was your Cerges? I am thinking about building one using a 20" housing with 1" ports and packing it out with more media and hair bun sponges. This should help to break down the CO2 without reducing the 1" hose and sacrificing flow rate. If this is not enough, i may need to add a vertical chamber like a Rex also. The flow rate on these things is insanely high!

Bump:


Supa Mint said:


> I think that these have a 1" version: http://nilocg.com/co2-equiptment/
> 
> Good luck!


Fantastic find! Thanks very much. Not sure if the maximum 24" length would be enough to diffuse efficiently with the flow rate. Planning a 20" cerges build but might need something like this as a secondary in-line reactor.


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## MaroMan (Jan 6, 2010)

I do have the exact housing you are speaking about, the key to doing this is putting a T before the Cerges reactor where you can screw or glue in a reducer and barb to accept the CO2 line, much easier doing this than trying to drill into the housing and bring the co2 in that way. I also would not suggest putting a lot of media or sponges in the cerges. As the media clogs your flow will greatly diminish causing more issues within your tank. I've done it. I do put a fine polishing filter in it and clean it out almost daily but that is not for the co2 but actually to remove sediment floating through the water. I do like this as it is very easy to access and clean out. You have to make sure that you have the down pipe inside of the unit as the water comes in the top and leaves the top, the down tube forces the water to the bottom of the canister before returning to the tank side piping.


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## Chadmanfoo (Jan 10, 2017)

MaroMan said:


> I do have the exact housing you are speaking about, the key to doing this is putting a T before the Cerges reactor where you can screw or glue in a reducer and barb to accept the CO2 line, much easier doing this than trying to drill into the housing and bring the co2 in that way. I also would not suggest putting a lot of media or sponges in the cerges. As the media clogs your flow will greatly diminish causing more issues within your tank. I've done it. I do put a fine polishing filter in it and clean it out almost daily but that is not for the co2 but actually to remove sediment floating through the water. I do like this as it is very easy to access and clean out. You have to make sure that you have the down pipe inside of the unit as the water comes in the top and leaves the top, the down tube forces the water to the bottom of the canister before returning to the tank side piping.


Thanks MaroMan. I am planning a T before the reactor and a ball-valve both before and after it. I was planning on running the flow down the downpipe then up though 2 course sponges and large bio balls to break the large co2 bubbles down. I may have to experiment though since, as you said, this will likely restrict the flow rate. My concern is that without any media, the large bubbles will go straight through the reactor and into the tank without anything diffusing. I may eventually need to find the parts for a Rex Griggs to add inline if this doesn't work. Irritating since I am down around £90 after buying all the Cerges parts and media.


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## OreoP (Aug 12, 2016)

Chadmanfoo said:


> Thanks MaroMan. I am planning a T before the reactor and a ball-valve both before and after it. I was planning on running the flow down the downpipe then up though 2 course sponges and large bio balls to break the large co2 bubbles down. I may have to experiment though since, as you said, this will likely restrict the flow rate. My concern is that without any media, the large bubbles will go straight through the reactor and into the tank without anything diffusing. I may eventually need to find the parts for a Rex Griggs to add inline if this doesn't work. Irritating since I am down around £90 after buying all the Cerges parts and media.


I use a 20" housing for my Cerges reactor without any media inside the housing. The key, I found, was to have a high flow rate into the Cerges and then introduce some back pressure via a ball valve on the outlet. This will ensure proper diffusion of the CO2. Might loose some flow but for me this was not a concern as I use an independent pump.


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## Chadmanfoo (Jan 10, 2017)

OreoP said:


> I use a 20" housing for my Cerges reactor without any media inside the housing. The key, I found, was to have a high flow rate into the Cerges and then introduce some back pressure via a ball valve on the outlet. This will ensure proper diffusion of the CO2. Might loose some flow but for me this was not a concern as I use an independent pump.


That is a great idea. I plan to use 68mm downpipe (reducing into the 32mm opening) for the internal pipe so the flow opens up as it enters the reactor. Picture a Rex Griggs inside a Cerges hybrid.

I am hoping the reduced downward current will allow the bubbles to remain in the downpipe until dissolved. If I am correct, I should get excellent diffusion without sacrificing too much flow.

See attached (crude) image of what i am planning. I will probably just cut up a kitchen funnel to reduce the 68mm downpipe into the 32mm outlet.

What do you guys think?


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## Mick J (Mar 13, 2019)

Use pipe reducers from the plumbing shop and drop your pipe size down to the size you need on the return for about six inches prior to defuser and six inches after at which point you return to your original size pipework Like I did and job sorted. I also did the same for my in line heater which is a Hydor and that works spot on as well.


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## laterkater (Dec 30, 2016)

Mick - I have read things about reducing pipe size possibly hurting the filter in the long run, but I can’t find a definitive answer. Your solution is the one I would like to do though. Thoughts?


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## LiQuiD SmoKe (Mar 13, 2015)

Chadmanfoo said:


> I have just upgraded my filter to a Fluval FX6. I was previously running a 306 with a 16mm inline diffuser. The FX6 hosing is much larger (24mm/1") so my old diffuser is no good.
> 
> I have done plenty of reading but cannot find an inline diffuser which will fit this hose size. A reactor is probably therefore my best option but I have no idea which is best and available in the UK. I am looking at https://www.amazon.co.uk/Sera-7000281-Flore-Active-Reactor/dp/B0033GDCVC, but am not sure if the hose will fit. The Q&A section states 16mm inner diameter 22mm outer diameter so i guess not.
> 
> ...





Supa Mint said:


> I think that these have a 1" version: CO2 Equipment - NilocG Aquatics
> 
> Good luck!


For my FX6 I just have the atomizer in the tank placed right below the intake. It then gets full saturation inside my filter, then outputs to my custom spray bar on my 125g. I just turn my filter on and off to help degas the filter at the end of the night. So far it works great... When I was looking into a reactor though, I also found the Nilocg one that SupaMint posted. I also contacted them and Colin the owner, recommended this reactor for the FX6. NA Advanced Co2 Reactor | Advanced Version With By-Pass Valve With Clear Reactor Chamber




OreoP said:


> I use a 20" housing for my Cerges reactor without any media inside the housing. The key, I found, was to have a high flow rate into the Cerges and then introduce some back pressure via a ball valve on the outlet. This will ensure proper diffusion of the CO2. Might loose some flow but for me this was not a concern as I use an independent pump.


Question... I recently had a leak on my FX6 thanks to my poor plumbing skills installing an inline heater to my 125 gal. I replaced my hoses, and now my flow is ALOT stronger than it was. I was curious if adjusting the ball joints on each side would reduce pressure, without putting strain on the motor? Thanks in advance.


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## OreoP (Aug 12, 2016)

LiQuiD SmoKe said:


> Question... I recently had a leak on my FX6 thanks to my poor plumbing skills installing an inline heater to my 125 gal. I replaced my hoses, and now my flow is ALOT stronger than it was. I was curious if adjusting the ball joints on each side would reduce pressure, without putting strain on the motor? Thanks in advance.


Do not throttle the input of the filter - maintain this at 100%. Throttle the output valve to achieve desired flow rate.

I would also look at a reactor - either a Cerges or a RG type. Very cheap and easy to build and install.


Also, there is no reason to degas the FX6 - it has a built in cycle that degases twice daily.


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## LiQuiD SmoKe (Mar 13, 2015)

OreoP said:


> Do not throttle the input of the filter - maintain this at 100%. Throttle the output valve to achieve desired flow rate.
> 
> I would also look at a reactor - either a Cerges or a RG type. Very cheap and easy to build and install.
> 
> ...


Thanks for the input. Ill adjust now. 

I knew the filter degassed once a day (determined by the time the filter is shut off), but not 2 times. Ill try to pay more attention to it.. When I do "reset it" in the late evening (around midnight) a TONE of bubbles come out.


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