• You are viewing the forum as a Guest, please login (you can use your Facebook, Twitter, Google or Microsoft account to login) or register using this link: Log in or Sign Up
  • You can now follow UKAPS on Instagram.

CO2 Reactor UK sellers?

MrClockOff

Member
Joined
20 Aug 2020
Messages
227
Location
Bournemouth
@foxfish wishing you a swift recovery ❤️‍🩹

To all of you just wanted to ask if reactor gets a good water flow and slow CO2 injection (say it’s relatively small fish tank like up to 20g) would the undissolved CO2 still build up inside the reactor? Is Venturi line more common on larger tanks where injection rate is insane?
 

foxfish

Member
Joined
11 Oct 2009
Messages
5,021
Location
Guernsey
It is probably easier to set up a small tank and get a good even flow but in every case you need to think about the equipment and match it to the tank.
Generally speaking you will get more issues with a small reactor on a large tank than a large reactor on a small tank but some of us just like to mess around and do things for fun as much as do things the easy way.
 

Zeus.

Fertz Calc Meister
Joined
1 Oct 2016
Messages
4,591
Location
Yorkshire,UK
No 1 is something I have done, no 2 would be miles better but I dont know if it would work?
No 2 the recirculation will be going to the highest pressure before the venturi IMO 😬

No 1 why did you have the CO2 injection/feed from rg entering at venturi ? I would of thought there is no need as this CO2 is at pressure (or will be given a little time)

I am trying to do it with the minimum of ports for recirculation and injection

1630956250496.png

Its working well as injected CO2 is going though venturi and it is also recirculating well - well almost too well, can be a be noisy when CO2 and water is recirculated at times, been playing with needle valves on these reactors also.

Might work better with just one reactor also 🤷‍♂️
 

Wookii

Member
Joined
13 Nov 2019
Messages
3,160
Location
Nottingham
Sorry to hear of your health issues @foxfish I hope you make a speedy recovery from the surgery.

Does the venturi not dissolve the CO2 bubbles faster than a simple recirculating inlet? My understanding of the physics is GSCE grade at best, but I have a vague recollection there was something about the change in pressure immediately after the venturi that forces gas into solution faster than standard inlet. Whether that is still the case on a small relatively low pressure set-up like this I'm not sure.
 

foxfish

Member
Joined
11 Oct 2009
Messages
5,021
Location
Guernsey
Thanks for the positive vibes, I have to deal with a six week recovery including the next 10 day of doing virtually nothing!
I have always enjoyed making reactors, I absolutely loved messing with protein skimmers but I only have one low tech tank running nowadays so my reactors days may be over… not to say I dont enjoy watching you guys doing your thing :)
I will be more able to participate in conversion in a couple of days when I am back home.
 

Wookii

Member
Joined
13 Nov 2019
Messages
3,160
Location
Nottingham
Took one reactor out and see how it goes after all its dealing with 350litres not the 500L when full, plus with one reactor will be easier as no need to balance the recirculating CO2

View attachment 174003

Do you literally get no bubbles free floating in the vortex inside the reactor then? I has assumed with all that water flow there'd be a little spiralling whirlpool of bubbles all the way down the reactor.

Also, have you modified then gas outlet on the inside of the reactor with any tubing to reach right to the top of the reactor?
 

Zeus.

Fertz Calc Meister
Joined
1 Oct 2016
Messages
4,591
Location
Yorkshire,UK
Do you literally get no bubbles free floating in the vortex inside the reactor then?
I did when I used then as designed but when I had the two attached and venturi working the flow wasn't enough to create a vortex, how ever this morning after removing one reactor after fitting the vertex returned as one reactor was getting all the flow.
have you modified then gas outlet on the inside of the reactor
No mods done to the reactor at all, which is a plus-plus IMO. Done little vid so you/folk can see the inside of reactor ;)
 

Wookii

Member
Joined
13 Nov 2019
Messages
3,160
Location
Nottingham
Ah ok, I was planning on adding a little U-shaped bit of tubing to the inside of the reactor, on the output to the venturi, so that the gas pocket inside is sucked out almost completely, as there must be a good half inch of gas left otherwise.
 

Zeus.

Fertz Calc Meister
Joined
1 Oct 2016
Messages
4,591
Location
Yorkshire,UK
Ah ok, I was planning on adding a little U-shaped bit of tubing to the inside of the reactor, on the output to the venturi, so that the gas pocket inside is sucked out almost completely, as there must be a good half inch of gas left otherwise.

@Hanuman when he did his reactor did a lot of reading around, he found the advice from Barr Report was to have a pocket of CO2 at the top of the reactor as they worked better, maybe this creates more pressure on the CO2 in side the reactor and gets the CO2 going to the DIY venturi better ? With the Ebay venturi I got there is no issue with the suction from the venturi at all except maybe too good. Plus the E Bay venturi is cheaper than making your own
 

dw1305

Expert
UKAPS Team
Joined
7 Apr 2008
Messages
13,863
Location
nr Bath
Hi all,
but I have a vague recollection there was something about the change in pressure immediately after the venturi that forces gas into solution faster than standard inlet.
I think gases will be more soluble at higher pressure, so the venturi itself will lower solubility (although I'd guess not significantly), but you would have more gas in solution.......... I'll stop there because I realise I'm well out of my depth.

cheers Darrel
 

Zeus.

Fertz Calc Meister
Joined
1 Oct 2016
Messages
4,591
Location
Yorkshire,UK
There will be a pay off between surface area of CO2 in contact with water, pressure of water and also water flow near the surface area, as in the later CO2 diffuses 10,000 times (Ten Thousand) slower in water than air, so the higher the flow/turbulence at the water/air interface the flow/turbulence will help maintain a better diffusion gradient. IMO thats why @foxfish reactor worked so well with the 'Vortex of Death'
 

Hanuman

Member
Joined
4 Jan 2019
Messages
1,358
Location
Thailand
@Hanuman when he did his reactor did a lot of reading around, he found the advice from Barr Report was to have a pocket of CO2 at the top of the reactor as they worked better, maybe this creates more pressure on the CO2 in side the reactor and gets the CO2 going to the DIY venturi better ?
The pocket of gas accumulating is just a by-product of the CO2 and other gases not being able to dissolve fast enough in the water. Now, to improve dissolution I figured that it would be best to have a conical shaped top which would force CO2 to constantly force its way against the incoming water. Having a flat top made some of the gases stagnate at the top uselessly. That was the primary purpose, it was not to have the ventury work better. In fact in a highly efficient reactor you would hardly need a ventury port. Reality is that I hardly see much of Co2 accumulating at the top although the Co2 injection rate is quite high. I can't count the bubbles. It's a constant flow. Whatever accumulates ends up being dissolved after the CO2 has been switched off. And I see no significant flow variation between Co2 on and off, because that's actually the only purpose of having a ventury port. To prevent back pressure and consequently water flow slowing down.
 
Last edited:

Hanuman

Member
Joined
4 Jan 2019
Messages
1,358
Location
Thailand
Hi all,

I think gases will be more soluble at higher pressure, so the venturi itself will lower solubility (although I'd guess not significantly), but you would have more gas in solution.......... I'll stop there because I realise I'm well out of my depth.

cheers Darrel
I think you are right. My new designed has a conical shaped top and I am injecting CO2 as a higher rate than before, yet I am seeing less CO2 accumulating at the top vs when my reactor has a flat top.

I am note sure of this but I think water temperature also plays a role in CO2 solubility so at identical CO2 and water rates, any given reactor could have more or less CO2 accumulating at the top. I could be wrong.
 

Zeus.

Fertz Calc Meister
Joined
1 Oct 2016
Messages
4,591
Location
Yorkshire,UK
In fact in a highly efficient reactor you would hardly need a ventury port.

Agree 100%

Without an air/CO2 pocket there would be no need of a venturi.
Venturi is just a means of increasing the surface area the gas has to diffuse though.
 

Hanuman

Member
Joined
4 Jan 2019
Messages
1,358
Location
Thailand
Without an air/CO2 pocket there would be no need of a venturi.
Indeed. The thing is that even if the pocket remains small you don't actually need a ventury port. I would say it would only be useful if you have large amount of CO2 accumulating.

Venturi is just a means of increasing the surface area the gas has to diffuse though.
My understanding is that Tom Barr's initial intention was nothing more than just releasing the back pressure as it would only kick in once accumulation at the top of the reactor happens at a certain depth and by the second half part of the day. The way you are using the venturi port is different as it looks like you are basically injecting CO2 straight to the venturi bar and any CO2 that would accumulate in the reactor would then be sent back to the venturi bar.

Have you tried without the venturi to see how efficient your reactor is and if there is was any CO2 accumulating throughout the day? If no accumulation happens or very minimal then I would think a venturi is redundant. In my case, my venturi was home made and is in fact quite weak. I am in fact considering removing it as it introduces complexity and a potential point of failure. I recently noticed some of the epoxy delaminating and I am concerned a leak could soon appear.
 
Last edited:

Zeus.

Fertz Calc Meister
Joined
1 Oct 2016
Messages
4,591
Location
Yorkshire,UK
The way you are using the venturi port is different as it looks like you are basically injecting CO2 straight to the venturi bar and any CO2 that would accumulates in the reactor would be then sent back to the venturi bar.
Correct

I would say it would only be useful if you have large amount of CO2 accumulating.

Which is what I had with the APS EF2
Have you tried without the venturi to see how efficient your reactor is and if there is was any CO2 accumulating throughout the day?
Not yet but have planned to try it :thumbup:

a potential point of failure.

Yes, if not needed, better with fewer joints.

It wouldn't surprise me to find below a certain size tank which will be pH drop/light/flow dependant there wasn't any benefit for using a venturi. If the CO2 reactor creates enough turbulence/vortex etc that will be enough and simply things
 
Top