# Fluval 306 and 5/8" tubing



## GeToChKn

The Fluval tubing being a ribbed pipe more than tubing is very thin, so it has almost the same ID as OD. It doesn't have a thickness like most tubing. Not sure what to use except try it on the filter, or even better, bring the double stop connector to your hardware store and test the connection to see what tubing it fits best.


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## AndreyT

Well, I'm planning to use inline heater and inline CO2 diffuser in this setup. These items have ~18mm external diameter on their connectors. I need tubing that will fit snugly over these connectors.

The next larger diameter for the tubing would be 3/4", if I'm not mistaken. That is ~19mm. So, theoretically, 5/8" is the right size for the tight waterproof fit, while 3/4" is too large. However, in real life 3/4" tubing will probably have smaller internal diameter than 19mm, which means that it might work for me as well.

This is basically why I'm asking this question: people who say they use 5/8" tubing, is your tubing only _labelled_ as 5/8" I.D.? Or did you actually _measure_ it and found it to be precisely 5/8" I.D.?


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## kevmo911

I never measured. If 5/8" was the tubing ID, I bought 5/8" ID tubing (at HD). Unfortunately, tubing wall thickness changes from brand to brand, so compression fittings can be a pain. But just fitting them onto barbs? That shouldn't be a problem.


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## SeattleFishGuy

I'm bringing this post back up because I just bought a Fluval 306 and am having the exact same problem. I have an inline heater and diffuser and there isn't enought stock tubbing with the Fluval so I went to HD and bought the 5/8 clear tubbing however as stated above the ID on this tubbing is 1/2'' and the ED is 5/8 so it won't work, even when I heated up the tubbing. 

So did the next size up in tubbing 3/4'' work? Anybody do this yet?


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## xmas_one

SeattleFishGuy said:


> I'm bringing this post back up because I just bought a Fluval 306 and am having the exact same problem. I have an inline heater and diffuser and there isn't enought stock tubbing with the Fluval so I went to HD and bought the 5/8 clear tubbing however as stated above the ID on this tubbing is 1/2'' and the ED is 5/8 so it won't work, even when I heated up the tubbing.
> 
> So did the next size up in tubbing 3/4'' work? Anybody do this yet?


Buy 5/8" id tubing. If it is sold as 5/8" id it will fit. Put it in boiling water for 10 seconds.


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## SeattleFishGuy

Yeah thanks I was just reading that somewhere else...someone also said to get 3/4 OD if I can find it. I'm buying some metal clamps too.

EDIT: There also is 7/8 OD which would be thicker but I wonder if it's too thick?


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## SeattleFishGuy

UPDATE:

Hopefully this will help the next person when they go down this road. What you need to do is go to your local hardware store (I went to Home Depot) and buy the tubing that is 7/8'' OD (Outer Dimension) and 5/8'' ID (Inner Dimension). This is great because if you get the 3/4'' OD and the 5/8'' ID the tubbing is thinner and can kink on the bends and it also doesn't fit the Fluval parts/fittings as well. The 7.8'' OD is much thicker wont' kink easily and has a nice tight fit, but not too tight that I even needed boiling water. I did buy SS clamps but I don't even think I will need them the fit it is so snug.

Anyway hope this helps somebody!


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## hdixon

SeattleFishGuy said:


> UPDATE:
> 
> Hopefully this will help the next person when they go down this road. What you need to do is go to your local hardware store (I went to Home Depot) and buy the tubing that is 7/8'' OD (Outer Dimension) and 5/8'' ID (Inner Dimension). This is great because if you get the 3/4'' OD and the 5/8'' ID the tubbing is thinner and can kink on the bends and it also doesn't fit the Fluval parts/fittings as well. The 7.8'' OD is much thicker wont' kink easily and has a nice tight fit, but not too tight that I even needed boiling water. I did buy SS clamps but I don't even think I will need them the fit it is so snug.
> 
> Anyway hope this helps somebody!


This is exactly what I was looking for. Gonna hit HD up today.:smile:


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## Lukeo85

The 5/8 ID hose from Ace worked well for me. It was a little snug on the end that goes on the aquastop valve. A little hot water will help it slide on the valve with a nice snug fit.


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## Nightspell

Excellent info guys, thank you. I'm also about to do this, I have the 5/8" I bought from Lowes in 10' coils. It fits, but not as snug as I'd like, and it's also kinked at several points from packaging. That was worrying me. The hose from the above picture looks ideal. Glad I didn't waste my time with it and cut it up yet so I can still return it...


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## sarahspins

Do yourself a favor and buy hose clamps - as the tubing ages it loses some elasticity, which means that you snug tubing may become less so with age.... and potentially pop off the fittings.


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## Sarah 'Shorty' Jacobs

Hey I know this is a rather old thread but im looking for some advice on water changing from the 306 filter. I have been told that you can connect pipes from the bit that plugs into the filter block? I'm struggling to get a pipe that fits I have green 16/22 pipe but even in hot water it will not connect has any one got any ideas on what I can do I have a door with a drain 3 meters from where the canister is and having to do it using buckets is hard work esp when I could just pop a hose on pop the red and grey bits up and then get on with other stuff as it's draining. Please help me 😞


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## AlePiek

SeattleFishGuy said:


> UPDATE:
> 
> Hopefully this will help the next person when they go down this road. What you need to do is go to your local hardware store (I went to Home Depot) and buy the tubing that is 7/8'' OD (Outer Dimension) and 5/8'' ID (Inner Dimension). This is great because if you get the 3/4'' OD and the 5/8'' ID the tubbing is thinner and can kink on the bends and it also doesn't fit the Fluval parts/fittings as well. The 7.8'' OD is much thicker wont' kink easily and has a nice tight fit, but not too tight that I even needed boiling water. I did buy SS clamps but I don't even think I will need them the fit it is so snug.
> 
> Anyway hope this helps somebody!


Thank you thank you thank you! 8 uears latet this post has been a blessing since the flu al 307 uses the same hose as the 306.


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