# Is a non-return valve required?



## scootamum (25 Jun 2015)

I've recently bought a full CO2 kit for a new aquarium that I am in the process of setting up.

One question though, do I need to insert a non-return valve in the tubing to prevent back syphoning of water from the tank?

It doesn't appear to have come with one, so not sure if I need one or not...

Apologies in advance if this is a stupid question.


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## ian_m (25 Jun 2015)

I have one in the CO2 line before my bubble counter and despite a one way valve being present in the bubble counter, water does work its way past the first valve, especially when changing the fire extinguisher and  system is allowed to depressurise.

Maybe your bubble counter has a better one way valve than mine.


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## scootamum (25 Jun 2015)

ian_m said:


> I have one in the CO2 line before my bubble counter and despite a one way valve being present in the bubble counter, water does work its way past the first valve, especially when changing the fire extinguisher and  system is allowed to depressurise.
> 
> Maybe your bubble counter has a better one way valve than mine.


 
Thanks Ian.  I hadn't realised that there may be one already present in the bubble counter.  Thanks for pointing this out.


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## zozo (25 Jun 2015)

Actualy since they work by laws of nature there is no return valve 100% water tight, even the best ones leave a a tiny bit water trough before they cut off, thats why they can get dirty. Usualy that's not the problem becayse a good closed system pulls a vacuum and the water beyond the valve will get stuck as soon it is closed and the vacuum builds up. Depending on the difusers density off course, cheaper bubbling difusers give less counter presure then the very dense more expensive misting difusers.

But there is one thing you just dont want to have and that is water in your needle valve nor in your regulator (or solemoid if you have one). If that happens the expenses can reach far beyond the cost of a return valve.  Actualy i use 2 return valves, 1 glass model because i love the looks. (The eye wants some too you know) and the second one i got right in front of the solenoid. Number 1 can get dirty and if for what ever reason it starts to leak trough still got a clean functioning  one at the solenoid...


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## scootamum (25 Jun 2015)

The kit does come with a solenoid, so that I can plug it into a timer for it to come on an hour before the lights do.

So it might be a wise investment then to buy another non-return valve then?

Where would you recommend I fit it?


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## ian_m (25 Jun 2015)

scootamum said:


> Where would you recommend I fit it?


After your needle valve and before your bubble counter.

I have one of these I got from Ebay Hong Kong, but also available from Aquaessentials. Has locking nuts. My first one way valve I bought, was clearly designed for airlines, as the rubber inside was attacked by the CO2 and melted as well as the plastic body cracking and the CO2 tubing frequently blowing off.


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## zozo (25 Jun 2015)

Actualy it's always wise to have at least 1 spare valve in case the other fails or needs a vinigar bath for a while to get it clean again, so you can bublle on in the tank. If ti is wise to put a second in line. I say yes, that's just because i worked with return valves quite a lot in other cases than co2 and i've seen them fail sometime.

And recomending one is difficult, i've read articals about very bad experiences with very expensive fancy return valves. So i'm not recomending, but i got a few almost the cheapest ones i could find and check 'm every time i clean the system. They are actualy such simple devices i can't imagine on made of gold be beter than one made of plastic. As Ian sais, buy one fit for co2, the rubber gaskets in there are not the most expensive parts, so the money is in the desing and casing.


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## scootamum (25 Jun 2015)

ian_m said:


> After your needle valve and before your bubble counter.
> 
> I have one of these I got from Ebay Hong Kong, but also available from Aquaessentials. Has locking nuts. My first one way valve I bought, was clearly designed for airlines, as the rubber inside was attacked by the CO2 and melted as well as the plastic body cracking and the CO2 tubing frequently blowing off.


 Thanks again Ian.  I'll definitely look into getting one from AE. 



zozo said:


> Actualy it's always wise to have at least 1 spare valve in case the other fails or needs a vinigar bath for a while to get it clean again, so you can bublle on in the tank. If ti is wise to put a second in line. I say yes, that's just because i worked with return valves quite a lot in other cases than co2 and i've seen them fail sometime.
> 
> And recomending one is difficult, i've read articals about very bad experiences with very expensive fancy return valves. So i'm not recomending, but i got a few almost the cheapest ones i could find and check 'm every time i clean the system. They are actualy such simple devices i can't imagine on made of gold be beter than one made of plastic. As Ian sais, buy one fit for co2, the rubber gaskets in there are not the most expensive parts, so the money is in the desing and casing.


 
Good idea to buy two.  Like you say, have a spare to hand in case one fails or needs to be descaled.

Thanks for all your help.


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## ian_m (25 Jun 2015)

scootamum said:


> a spare to hand in case one fails


In fact my UP one (same as in the photo) had issues as well.

I noticed one day that I was getting through CO2 at faster than 20gr a day, my normal rate, thus had a leak somewhere. Dunked all the CO2 bits, in a bucket of water and after a bit of wiggling a slight stream of bubbles was coming from the plastic joint on the one way valve. Put back my original CO2 one way valve (and 6mm hose clips) and decided to cut open the failing valve at the joint. After careful sawing, it looks like the two halves of the valve screw together with plastic cement supposedly sealing the final joint, this is where it was leaking as the cement didn't cover all the joint. However did discover the inside is a spring and silicone disk/valve, so that is good as silicone is CO2 resistant. Screwed back together with thread covered in plumbers LSX silicone thread sealer, put back into service and years later is still working (well at least using 20gr CO2 a day, so no leaks).  Keep forgetting to buy a replacement each time I order from Aquaessentials...


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## parotet (25 Jun 2015)

zozo said:


> Actualy i use 2 return valves, 1 glass model because i love the looks. (The eye wants some too you know) and the second one i got right in front of the solenoid


 I have also used two of them and it doesn't have any effect on the bubble counter or gas flow. Amazingly I bought a JBL CO2 check valve with threads, more expensive but supposedly more secure, and it failed (if I use this model I need an additional needle valve). Now I'm using the cheap ones and they are good enough to stop the back flow. My guess is that every check valve can be faulty, but from the design point of view, most models do well.
I usually place the check valve just under the bubble counter (thus, between the bubble counter and the solenoid. This way it is also easier to fill your bubble counter without much hassle or risk for breaking glass equipment: just disconnect the tubing under the check valve, connect another one and with a syringe introduce water through the check valve to the bubble counter)
However in one of my LFS I was told that in large tanks they put the check valve between the diffuser and the bubble counter because otherwise there is no check valve that can cope in the longterm with such a high pressure... not sure if it makes sense from the scientific point of view, but actually in all the large tanks they were placed like this.

Jordi


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## GHNelson (25 Jun 2015)

This is the configuration I always use Regulator /Solenoid > Check Valve > Bubble Counter > Check Valve > UP diffuser or Ceramic diffuser.
Ditch the plastic..... purchase some metal ones but even they can fail sometimes!
Co2 Art did have some better quality valves...have a look! 
hoggie


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## zozo (25 Jun 2015)

I use those 90 cent valves.. They are co2 save and and work well for low presure at around 0.5 bar.. Check it every morning anyway if i see water in the hose, thats the same habbit like always lock your bike.

2 failing at the same time is very unlikely especialy the one never getting dirty..  But after a while i sometimes see a bit water in the hose, then the glass checkvalve is dirty. But is i said, if the system is air thight it will pull a vacuum. WHen the co2 starts the water is pushed out again.

You know what the problem is these days? And that's the Japanese production system. Which is applied to 99.9% of all manufactured products all over the world. They don''t test anymore for durability. They take an existing blue print that prooved itself in the past and just make it with available material. Let the customer test it and regarding the feedback they get back the product gets enhanced whit better material or pulled from the line.

Take 30 years ago a car manufacturer had a test line, where for example a door was opened and shut automaticaly to see how long all parts will last. And that's history, now a faulty product gets called back if it's realy important. Testing days are over... You may do that for them thats much cheaper...


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## xim (25 Jun 2015)

All return valves I know need some force to press the seal shut, be it the force of water/air flowing back, or spring to press the sealing ball.

But in our CO2 application. CO2 in the line gets absorbed into the tank water, creating vacuum in the line.
Water moves into the line. Then the vacuum sucks open the check valve seal.

I have been using these: http://www.amazon.co.uk/Plastic-Non-Return-Aquarium-Check-Valves/dp/B006HB962O
They have been in use for 5 years now. No problem. I don't know why they work while the more expensive 
ones don't.

The ones that fail most are the barrel shaped ones.


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## Jose (26 Jun 2015)

scootamum said:


> I've recently bought a full CO2 kit for a new aquarium that I am in the process of setting up.
> 
> One question though, do I need to insert a non-return valve in the tubing to prevent back syphoning of water from the tank?
> 
> ...



Some bubble counters have a valve inside. You might want to double check yours before buying.

Ive got this one and works perfectly. Plus since its integrated into the bubble counter there are two co2 joints less in the system so less risk of leak.
http://www.co2art.co.uk/collections...-co2-bubble-counter-with-build-in-check-valve


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## zozo (26 Jun 2015)

Jose said:


> Some bubble counters have a valve inside. You might want to double check yours before buying.
> 
> Ive got this one and works perfectly. Plus since its integrated into the bubble counter there are two co2 joints less in the system so less risk of leak.
> http://www.co2art.co.uk/collections...-co2-bubble-counter-with-build-in-check-valve



I've watched those often, didn't buy because it just doesn't fit my way i want it to have. Good to know you're having good experience with it.
I recently found them like this.



Also interesting construction.


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## Jose (26 Jun 2015)

zozo said:


> I've watched those often, didn't buy because it just doesn't fit my way i want it to have. Good to know you're having good experience with it.
> I recently found them like this.



Sorry why dont you like them zozo?

If you dont want a bubble counter with a check valve included then I'd go for something like this:
http://www.co2art.co.uk/collections...ight-quality-brass-co2-check-valve-non-return
I would buy everything in your co2 line with this type of connection. It will safe a lot of headaches. Forget about the push in ones unless you are using a low preassure system. But if using an atomizer I find the threaded connections to be a must.
Also put the checkvalve before the bubble counter as near to it as possible or youll get water in the line between the two. If line is a bit long then all the water might not flow back.


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## zozo (26 Jun 2015)

No  i like 'm very much, before i did set up my Co2 i just was putting things on my wishlist. And while looking and searching around i fancy the industrial looking stainless steel, aloy materials and the laboratory like glass ware.

Putting al together i found and compared i came to fancy a glass setup the most after all the aqaurium is glass and fits best.. That's why i decided not to go for the industrial metal looks.

So i went for the glass filter ware, diffuser, bubble counter, check valve and i love it.. Looks like a retro laboratory setup.   Did fasten the diffuser to the filter inlet and every bubble is sucked in there and passes trough the filter first.

I have no reason to complain it already works for months now and as long as i don't brake it, it will last me a life time.

Actualy to fancy it up a bit i'm planing to make me a diy acrylic rigid piping system to get rid of the wobly hoses.  than i'll be excactly where i want it to have.. Yes!!


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## Jose (26 Jun 2015)

zozo said:


> No  i like 'm very much, before i did set up my Co2 i just was putting things on my wishlist. And while looking and searching around i fancy the industrial looking stainless steel, aloy materials and the laboratory like glass ware.
> 
> Putting al together i found and compared i came to fancy a glass setup the most after all the aqaurium is glass and fits best.. That's why i decided not to go for the industrial metal looks.
> 
> ...



Yes I understand this. We can criticize ADA all we want but the aesthetics is just great. Like you say it just looks very profesional even though some things are not the best/most efficient.


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## zozo (26 Jun 2015)

Jose said:


> Yes I understand this. We can criticize ADA all we want but the aesthetics is just great. Like you say it just looks very profesional even though some things are not the best/most efficient.



Maybe it's just me  i don't see it being inefficient.. I see it work and some minor things i can overcome with tuning it a bit by myself. That's just what i love to do. That's what the Japanese jused to love and how they made a name for them self in the industrial revolution, steel ideas and enhance them. But they too are getting lazzy i guess.. lol.. I would be a good old fashion Jap..


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## Jose (26 Jun 2015)

zozo said:


> Maybe it's just me  i don't see it being inefficient.. I see it work and some minor things i can overcome with tuning it a bit by myself. That's just what i love to do. That's what the Japanese jused to love and how they made a name for them self in the industrial revolution, steel ideas and enhance them. But they too are getting lazzy i guess.. lol.. I would be a good old fashion Jap..



Hehe, I really had their diffusers in mind, also the lights etc.


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