# Ista bottles/regulator how to identify thread type? Sodastream conversion?



## neofy705 (21 Nov 2020)

Hello all,

Long time lurker first time poster  This is my first time using pressurised CO2 in my tanks.
I bought an ista pressurised system off marketplace for £30 which i thought was amazing value. The "premium" ista kit, it has a 0.5L refillable cylinder, a solenoid etc.

The system worked beautifully in my 54L tank... until it needed a refill. 
The bottle clearly states 5/8-18UNF (same as disposable 95g)  so I bought a sodastream to nano adaptor and a sodastream cylinder and it turns out the ista bottle is clearly not 5/8-18 unf, using a ruler the thread measures 21-22mm much bigger than what a 5/8-18UNF should be. 

Does anyone have any experience with the ista setup? What do I do now? 
Does anyone know what the ista bottles/regulator thread type is? 
I asked a number of retailers/sellers and they all said it's din477 but a quick search here shows quite a few members had incompatibility issues.
I'm on a budget and I've already wasted £35 on a sodastream conversion that failed.

As I'm only running 1 bubble per 3 seconds I thought a sodastream would be ideal for me.
But now I don't know what to do. Options:
1) Send the ista bottle for a refill via someone i found on ebay (£15) and have no co2 for a week?
2) find an adaptor that can make my regulator use sodastream? I can find DIN477, CGA320, G5/8 but which one is it? And will it work or is my regulator only compatible with insta cylinders so option 1?
3) try all possible adaptors (between 20-22mm) with the risk of just wasting another £30?

 Any help will be greatly appreciated.


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## dcurzon (21 Nov 2020)

Standard UK fire extinguisher is w21.8 which sounds like what you have there.
Either pick up a co2 fire extinguisher, my last one was £15 delivered (2kg), or pick up a w21.8 to sodastream adaptor, which will be about a tenner.   
(And handy to have around anyway)


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## neofy705 (21 Nov 2020)

Thank you, dcurzon. The thing is I'm not sure if my bottle is w21.8. It could be a cga320 or a non standard one. The inside of the regulator looks like it has something. Do the male and female parts look like a w21.8 to you?


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## Nick potts (21 Nov 2020)

The Insta regulator is a CGA 320, not a w21.8/din477 thread.

To use a sodastream you will need an adapter like this one https://www.co2supermarket.co.uk/sodastream-cylinder-valve-adapter-advanced-p171.html, a FE will be cheaper in the long run


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## neofy705 (21 Nov 2020)

Nick potts said:


> The Insta regulator is a CGA 320, not a w21.8/din477 thread.
> 
> To use a sodastream you will need an adapter like this one https://www.co2supermarket.co.uk/sodastream-cylinder-valve-adapter-advanced-p171.html, a FE will be cheaper in the long run


OMG thank you Nick. Do you use the insta reg yourself?


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## jonnyuk (27 Dec 2020)

sorry to drag up an old thread but i'm in the same position as you where. i have actually send mine off to be re-filled via ebay but would want  a longer term solution.
what did you do you in the end?


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## neofy705 (27 Dec 2020)

In the end I bought a different regulator for sodastream cylinders. There was nothing wrong with the ista reg or bottle. In fact I was very happy with the whole setup, I still have it as a backup.
I bought some vernier callipers and did a lot of research. The thread size of my bottle seems to be 21.6mm instead of 21.8mm. It appears to be a loose din477. I believe the bottle should be refillable like any other and that you can use the bottle on any regulator. Now the ista regulator if it's also 21.6mm (can't measure this) then it means it's only good for an ista bottle. I haven’t tried using it with a fe though.


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## jonnyuk (28 Dec 2020)

cheers for the update, i may just buy a second bottle and then i can swap them, i've only got a 55ltr tank so one bottle should last some time (i only bought it about 3 weeks ago and it emptied within a few days, i think somewhere in my plumbing i had a leak


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## neofy705 (28 Dec 2020)

You deffo had a leak. My 0.5l ista lasted a while and it was half empty when I got it.


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## CO2-FILLER (20 Jan 2021)

the ISTA UNF thread is slightly different to DIN177 and W.21.8 when connecting to the male UNF to refill your ISTA cylinder. I had to get an adaptor custom made to refill ISTA cylinders as my pump would not connect securely as it does to DIN177 and W.21.8 equivalent. CO2 Supermarket do an adaptor for female, but not male. If you're doing your own refills, from a mother cylinder, I can put you in touch with the CNC company that made the adaptor for me.


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