CO2 not fully dissolved (ext reactor)

[ciscube]

Hi,

I bought a NA external reactor and it's driven by ATMAN 3338. I found that there is still some small undissolved CO2 coming from the outlet.

I'm suspecting that the filter is too strong and blowing out some of the CO2. Any advise?

[BFG]

How did you placed the external reactor? The glass part should be on top, not the plastic base. That could be the reason the bubble escaped.

[ciscube]

yep, I did just that. Plastic base is on the bottom, as what Chan had in his display tank, but without the ceramic rings.

[BFG]

Is the reactor full of water, half filled with water or only the plastic base area is filled with water?

[ciscube]

It's full of water, only left maybe 0.5cm air at the top. Actually, I had tried to slow down the filter by adjusting the output tap, it's better but still have some bubbles coming out and the worse part is that the gap of CO2 at the top is increased to about 2cm merely after 2hr. So I put back to full power again.

[PeterGwee]

Fill up the entire chamber with bioballs to improve gas exchange. With nothing in there, all the gas exchange can only occur with the water jet stream and single layer of water surface as the O2 degas inside the reactor.

Regards
Peter Gwee

[ciscube]

Hi Peter,

If the reactor is filled with bio-balls, I'm not sure whether the bio balls had any space to spin . And won't the extra blockage caused the water flow to slow down, and effectively won't it have the same effect as slowing down the filter (more Co2 gap at the top)?

[vinz]

The external reactor is quite efficient in my experience... i was running it at 1000l/hr before and never had this problem. Now I'm running at 2400l/hr but with a chiller in line as well... and still don't have this problem. What is the flow rate of your filter?

Perhaps you should look at your CO2 injection rate? Perhaps it is too high. Have you checked the CO2 level in your tank? Is it within range?

[BFG]

I agree with Vinz. This reactor is highly efficient. The top part where the co2 gas is collected is normal to me. The gas would be absorbed into the water while the water is spinning in the reactor. Ime, there's no need to add anything to the reactor. There should be a rubber hose inside the reactor though as this would serve to push the water to a direction in the reactor.

[ciscube]

Hi Vinz,

It's a long time since I had measured KH and PH I used my gut feeling, I think currently it is about 10bps. To me, as long as there is no BBA, the fish is ok and the plants are bubbling a lot within 4hrs, I think the CO2 content is ok. What's bothering me now is I can see CO2 bubbles going horizontally and this contradict with the O2 bubbles going vertically up So quite visually quite messy.

[vinz]

Ummm... how big is your tank? I think your CO2 injection is too high. Reduce it till you get less/no bubbles escaping and still able to maintain no more then 0.5cm layer of CO2 at the top of the chamber. Afterall, the bubbles that escape will not conrtibute much to the tank CO2 level anyway.

[ciscube]

Opps..forgot about the tank information

Tank size is 5ft x 2ft. I'm using 2 ATMAN 3338 (flowrate:1200l/hr) driving 2 external reactor and the outlets are pointing to each other at the back of the tank. The outlet is positioned at different level, so the current will not crash at each other, else I will see lots of CO2 bubbles coming towards me

One of the bubble counter is about 10bps, the other not sure as the bubble counter water almost gone.

I will try to reduce the bps to check if it helps, of course not at the expense of cultivating BBA

[tawauboy]

Fill up the entire chamber with bioballs to improve gas exchange. With nothing in there, all the gas exchange can only occur with the water jet stream and single layer of water surface as the O2 degas inside the reactor.

Regards
Peter Gwee

Peter,
how did you open na external reactor to fill it with bioballs. seems to be glued tight.

[PeterGwee]

Peter,
how did you open na external reactor to fill it with bioballs. seems to be glued tight.

I'm not using that reactor anymore but I did manage to force it open last time using brute force. I didn't really like that reactor as the inner tube design tend to come off after some time or worst drop into the incoming flow path obstructing everything. I rather DIY one based off Ghazanfar Ghori's design and perharps add the venturi loop design if you use a powerhead to drive it. Helps keep up the efficiency of the reactor as the O2 degas in the reactor during the day. Main issue is still to keep the flow to the reactor as high as possible without burping issues. More flow equals to more mixing and better response time.

Regards
Peter Gwee

[Rupert]

I have a NA external reactor, powered by a Eheim 2028. I did try to open it a few times to get to the bio balls as they seemed too big and they do not spin, but it must be glued shut.

Setup:
2028=>Chiller=>Reactor.

I had it set up with about 3 bubbles per second, but found a pocket of co2 would form within the reactor after a while and bubbles would be expelled, have since changed it to 2bps.

You can also use the Dennerle formula for the minimum of bubbles per minute [BPM], Water Volume in Litres x ◦dkH divided by 50. eg Effective volume 420 litres x 4 ÷ 50 = 33.6 BPM, or 0.5 bubble per second.

[BFG]

er, you guys did not get the tool when buying the reactor? I had the plastic tool to open up the reactor.

[vinz]

Yeah... why do you need glue? I was suppose to have a tool (big plastic wrench like one), but I don't know what happened to it. Anyway, I open and close mine with my bare hands (and I'm not strong like BFG... barely pass IPPT type).

As for the tube in the middle dropping in and blocking the flow... just cut the bottom diagonally, and make sure that pipe faces the correct way.

[Rupert]

Thanks for that... I bought mine 2nd hand... didn't know about the tool.

[hii]

The CO2 reactor from NA is actually modify from the pipe filter which center have a white filter pad. I think you can get it from most hardware shop. But have to drill a small hole at the cap there for CO2 injection.

With a hand it is impossible to open it, that's why it include a plastic opener together with the filter in the box. But with the opener it also hard to open cause you need something to hole the cap so it won't turn when u turn the opener.

Personally I prefer to use the filter pad cos it help to diffuse CO2 and same time filter you water too.....anyone have any idea will the filter kill all the bacteria + CO2 ??

I plan to change my internal CO2 reactor to external type soon....

[tawauboy]

I'm not using that reactor anymore but I did manage to force it open last time using brute force. I didn't really like that reactor as the inner tube design tend to come off after some time or worst drop into the incoming flow path obstructing everything. I rather DIY one based off Ghazanfar Ghori's design and perharps add the venturi loop design if you use a powerhead to drive it. Helps keep up the efficiency of the reactor as the O2 degas in the reactor during the day. Main issue is still to keep the flow to the reactor as high as possible without burping issues. More flow equals to more mixing and better response time.

Regards
Peter Gwee

got the reactor quite sometime back and tried to open it but failed. so it is gathering dust somewhere. wanted to open it to change the co2 inlet and add some bioballs. the reactor needs some modification...