[PlantedRich]

There always lots of folks just starting the trip down the CO2 path and most do agree there is a pretty steep learning curve involved so I thought I might post this warning.
It can all go bad and sometimes it does it really quick! I thought I had a handle on making changes really slow and gradually but that was not good enough today. I came within a short of killing the whole tank and I'm still working out what went wrong. One thing that made recovery much harder was that I did two things at once. I should know better!!!
One was a 50% water change and that used up my reserve water supply so that my new water was still cold. Water lines here are not buried deep so the new water in the barrel was about 60 F.
I normally treat it and let it warm up before I need it in the tank but today was a total wreck.
After the water change, I bumped the CO2 just a touch and that was too much. I have a 120 gallon and using a Grigg's style reactor, I push too many bubbles to count so adjusting is just a small touch that can't be seen to count the change.

I was here and watching but within two hours I had major trouble with fish nearing death.

With lots of new water, adding hot water from the sink to maintain a reasonable temperature, and lots of powerheads and circulation they have all recovered but it was a close thing.

 

[galabar]

One thing that confuses me is that you say you are using a Grigg's reactor. However, you can't count the bubbles. For any 100% efficient method, you shouldn't need that much CO2 for a 120.

Maybe others can chime in here (especially if you own a similar sized tank).

 

[PortalMasteryRy]

The efficiency of the C02 injections does not really translate to 100% distribution of the C02 in the tank.

C02 levels are not the same at every part of the tank hence the reason of injecting more or injecting earlier (2 hours or more...I start my injection 4 hrs before lights turn on). It also helps to have good water circulation and flow to ensure that the C02 enriched water is being distributed properly.

This is the reason why some people have multiple drop checkers at different locations in their tank to confirm that adequate C02 levels are present in those parts of the tank.

Hardscape and plant mass can also affect the flow of water and hence affect the amount of c02 present where you have poor circulation at that area.

 

[galabar]

The efficiency of the C02 injections does not really translate to 100% distribution of the C02 in the tank.

C02 levels are not the same at every part of the tank hence the reason of injecting more or injecting earlier (2 hours or more...I start my injection 4 hrs before lights turn on). It also helps to have good water circulation and flow to ensure that the C02 enriched water is being distributed properly.

This is the reason why some people have multiple drop checkers at different locations in their tank to confirm that adequate C02 levels are present in those parts of the tank.

Hardscape and plant mass can also affect the flow of water and hence affect the amount of c02 present where you have poor circulation at that area.

I was referring to 100% absorption of the CO2, not 100% dispersion throughout the tank. I don't think anything you said contradicts my assertion that an uncountable stream of bubbles it probably too much for a 120g tank.

 

[kevmo911]

I was referring to 100% absorption of the CO2, not 100% dispersion throughout the tank. I don't think anything you said contradicts my assertion that an uncountable stream of bubbles it probably too much for a 120g tank.

I'm going to have to disagree. With the caveat that nothing is standard, I believe that unless somebody is running a very low CO2 level, they're not going to be able to do any counting for a 120g. I had a 30g with a Grigg, no bubbles, no leaks, and did 3-4 bps in a standard JBJ bubble counter. I can't count with my eyes past about 4, and can count - carefully - by ear up to about 6. I would have run 12-16 bps on a 120g with that bubble counter, and I wasn't very near redline.

 

[jrill]

I was referring to 100% absorption of the CO2, not 100% dispersion throughout the tank. I don't think anything you said contradicts my assertion that an uncountable stream of bubbles it probably too much for a 120g tank.

Nope, I think your way off. A 120 would take a fair amount of bps. More than I could count.

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[PlantedRich]

One thing that confuses me is that you say you are using a Grigg's reactor. However, you can't count the bubbles. For any 100% efficient method, you shouldn't need that much CO2 for a 120.

Maybe others can chime in here (especially if you own a similar sized tank).

Are you saying you are able to count the number of bubbles on your large tanks? I've read that some do it by recording the flow and getting an estimate by slowing the video down but I've never tried that.

Unless the drop checker worked much quicker than any I've used, it would not have changed color quick enough to help. The drop checker usually takes a few hours before a change shows for me. The fish would have been dead long before the color changed.

At this point all the fish have recovered and look fine but I'm still not certain that the adjustment was the total problem. We recently had a discussion of what the poster called "super saturation" and it makes me wonder if I did not have something of the same problem.
At the end of my water change, I ran out of reserve water, treated a second barrel full and used about 10-15 gallons of the new water to top off the tank. That amount of new 60 degree water did not drop the tank temp. enough to worry. Something like .5 degree.
But when I got done with the panic, I found the same bubbles the other poster showed except different places.
He had added wood to the tank and thought the wood to be a problem. I did no changes other than water and CO2 adjustment.
But when I finished had bubbles all over the temporary powerheads. A few bubbles in the plants and algae but not on the Eheim input/output but totally covering the powerheads!
Super saturation? Some type of reaction from the new water that nearly killed the fish but more of that new water during the water change helped them recover? I'm still thinking about this question as it doesn't seem to make sense.

 

[hbosman]

I'm going to have to disagree. With the caveat that nothing is standard, I believe that unless somebody is running a very low CO2 level, they're not going to be able to do any counting for a 120g. I had a 30g with a Grigg, no bubbles, no leaks, and did 3-4 bps in a standard JBJ bubble counter. I can't count with my eyes past about 4, and can count - carefully - by ear up to about 6. I would have run 12-16 bps on a 120g with that bubble counter, and I wasn't very near redline.

I only have a 57 and when i used to use a bubble counter, I couldn't count it either. And, 5 lb cylinder still lasted 6 months.

 

[PlantedRich]

Part of what has me stumped is that I was not running near the level I used to run when the tank was fully planted. I had placed a red mark on the needle valve at that time and all was fine for long enough for me to decide that it was more work than I liked. So I began to back down and had totally shut off the CO2 for about a month as I was pulling plants down to what I wanted. I have been working back into feeding CO2 over the last couple weeks and yesterday was just a tiny bump to get a small amount more CO2.
My first thought was that , even though I was going very slow, I almost killed the fish. But now that I have the fish right again and find the bubbles collecting on things, I have to wonder what and why the fish were suffering. If it was too much CO2, I'm surprised but if it was something else, I'm totally confused!
With two filters and two powerheads, I felt the circulation was good enough.
If the bubbles are CO2 collecting on things, I would have expected the fish to die instead of recover?

 

[mistergreen]

Do you have surface agitation? If not, CO2 concentration builds up fast.

 

[PlantedRich]

Do you have surface agitation? If not, CO2 concentration builds up fast.

Not splashing but there is a pretty good ripple depending on how high/low the waterline. Two canisters, a 2217 and a 2075 are both pulling from near the bottom and pushing it back in at the top. No spraybars as I like the way the full flow moves things further across the longer tanks. With two powerheads moving water around nearer the bottom, there should be little to no dead areas. I would have expected the 50% water change to have reduced the CO content to a pretty low level?
I might have guessed the CO2 would not have fully recovered in the couple hours it took between the water change and the fish distress.

I'm mixed on my thinking on that point. If the water was just totally saturated, I might have expected bubbles on things but it seems strange that there were bubbles in limited places rather than all over. None on the glass, very little that I could see on the wood and rocks, none on the Eheim filter tubing but lots on both the Marineland and the nano powerheads. Some that appeared to have been blown around was in the algae and on some of the plant leaves.
Does the amount of bubbles on the powerheads seem to show a really high CO2 content to you other folks?

The sudden change from normal routine water changing to fish almost dying is what has me baffled. I'm hoping to learn something from this event but right now, I'm not sure what that "something " is going to be.
:frown2:

 

[nilocg]

Please delete.

 

[mistergreen]

Yeah, if your going to push limits, you'll need splashing to add O2. There won't be noticeable bubbles. I pumped 135ppm of co2 into a bucket with no visible signs.

Your fish were probably getting 80-90 ppm of co2.


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