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Discussion Starter · #1 ·
Finally had my co2 dialed in, plants looking healthy and now it appears I'm having an issue. I turned off the jebao 8000 pump, the co2 and let the overflows drain, then I switched the pump back on and a ton of co2 came rushing out into the tank. I waited for awhile until all the bubbles were gone and the tank had stabilized then I turned the co2 back on, still no co2 coming out. Any ideas?
 

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I'm not sure I understand what your issue is? CO2 should not be coming out of the rex grigg. The entire point of the rex grigg is to keep the CO2 inside of it while it dissolves so you only get CO2 rich water out of the end of it.

Over several hours if the CO2 rate is high enough the gas will not completely dissolve in the water and CO2 will build up inside the rex grigg reactor. Since it is still in direct contact with the water and has nowhere else to go the CO2 will still dissolve as fast as possible into the water however it can become slightly noisy. If you turn off the pumps and then blast them back on it is possible to push this large CO2 bubble out all at once, though I don't know why you would want to do this as it can be dangerous to your fish. The trapped CO2 will continue to dissolve after you turn off the CO2 for the night and will be gone within an hour or two.

Alternatively you can drill a small hole in the top of the rex grigg reactor and put tubing in it to act as a bleed off. This bleed off can either be connected to nothing and just open a valve on the end of it for a few seconds each day to bleed off the excess CO2, or it can be fed into a higher velocity (lower diameter) pipe which will use the venturi effect to push the gas from the low flow section into the high flow section, allowing it to escape.
 

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Discussion Starter · #3 ·
I'm not sure I understand what your issue is? CO2 should not be coming out of the rex grigg. The entire point of the rex grigg is to keep the CO2 inside of it while it dissolves so you only get CO2 rich water out of the end of it.



Over several hours if the CO2 rate is high enough the gas will not completely dissolve in the water and CO2 will build up inside the rex grigg reactor. Since it is still in direct contact with the water and has nowhere else to go the CO2 will still dissolve as fast as possible into the water however it can become slightly noisy. If you turn off the pumps and then blast them back on it is possible to push this large CO2 bubble out all at once, though I don't know why you would want to do this as it can be dangerous to your fish. The trapped CO2 will continue to dissolve after you turn off the CO2 for the night and will be gone within an hour or two.



Alternatively you can drill a small hole in the top of the rex grigg reactor and put tubing in it to act as a bleed off. This bleed off can either be connected to nothing and just open a valve on the end of it for a few seconds each day to bleed off the excess CO2, or it can be fed into a higher velocity (lower diameter) pipe which will use the venturi effect to push the gas from the low flow section into the high flow section, allowing it to escape.


Thanks for reply. My mistake, before I never really had 100% dissolved co2 as I don't think i have a big enough reactor. I could see some micro bubbles coming out but never was it fully dissolved, now I don't see any micro bubbles either. I start the co2 an hour before the light come on to build up the concentration, yet still today my drop checker has never turned green. Perhaps the reactor somehow suddenly started doing a better job but that seems unlikely to me. Although I wouldn't know, maybe there's a break in period?

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That does seem weird. Did your drop checker turn green before this incident? Its possible something got clogged or there is a block or something. It's hard to know for sure. What pressure are you running the CO2 at? You might try increasing the regulator pressure to see if that helps unblock it or makes any change.
 

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That does seem weird. Did your drop checker turn green before this incident? Its possible something got clogged or there is a block or something. It's hard to know for sure. What pressure are you running the CO2 at? You might try increasing the regulator pressure to see if that helps unblock it or makes any change.


The drop checker was turning a bright green an hour or so after the lights came on, now it's solid blue all day. I've tried going from 30 psi to 50 and opening the needle valve until there's a solid stream of bubbles and still nothing. Only thing I changed recently was a piece of leaky tubing, but I know the bubbles are making it through since they all fly out when I turn the pump off and on.

I even mixed a new batch of 4dhk and pH reagent, thinking maybe the other one went bad somehow.


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I would suggest a good thorough leak check. Leaks are one thing we often find ignored and it can cost us a tank of gas. Since the high pressure meter on the tank doesn't start to move down until we have used all the liquid CO2, we can go along thinking we are pumping lots of gas into the tank while we are really just pumping it into the room.
Do you test with soap after making changes like tubing?

NOTE to all? Is it fair to say we are using a Rex Grigg's reactor if we have changed and made mods to the design?
 

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Discussion Starter · #7 ·
I would suggest a good thorough leak check. Leaks are one thing we often find ignored and it can cost us a tank of gas. Since the high pressure meter on the tank doesn't start to move down until we have used all the liquid CO2, we can go along thinking we are pumping lots of gas into the tank while we are really just pumping it into the room.

Do you test with soap after making changes like tubing?



NOTE to all? Is it fair to say we are using a Rex Grigg's reactor if we have changed and made mods to the design?


Yeah it has been thoroughly leak checked, again the bubbles are coming out when I turn off the pump and turn it back on, so I known co2 is making it in the reactor. I haven't made any changes to the designs that I've found, granted Rex griggs original post on the reactor doesn't have pictures up anymore. Nilocg talked me through it though. I'm afraid to leave the co2 up too high when trying to clear the reactor as I don't want a large mass to come out and kill all my fish.
 
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