CO2 issues....

[HiJaC]

Hi,

I've put in my JBL (set 3) CO2 kit in my planted tank a few weeks ago. After an initial issue with my running in time (left it on a bit too full) and a PH crash i have been trying to calibrate it over the last couple of weeks.

It comes with a nice PH monitor that cuts off the gas when it gets below a set PH (which i was putting at 6.8 for now).

KH is 4 btw.

So after the PH crash (in which i lost one Rummienose) i was letting the tank recover by leaving the gas off. The calibration was more of a hassle as i tried various ways of taking into account the temperature difference between the tank and the buffer solutions. Eventually i went for the "leaving the buffer solutions in a bag of tank water in the tank for 12 hours" method and am at a level where I think the calibration is correct.

So i did a big water change (75%) yesterday to reset the tank proper before turning the dosing back on. Running about 30 bbm, just to see how fast it would drop from the initial 7.3 of the tank. I left it happyily knowing it wouldnt keep gassing away post the level of the 6.8 i wanted it at.

I check again this lunchtime (lights still off) to find the tank is at 6.66 which is the level i kind of expected it to be after a night of the plants & fish breathing out CO2 all night.

From experience the tank will get back to 6.8 by about 8/10th's of its way through the lights on part of the day. At which the CO2 should switch back on.

Issues.

After i crashed the PH the first time alot of the fish were up at the surface trying to get oxygen. Even after I turned off the CO2 and did some water changes I still found the Dwarf Cichlids there every morning, and one of them practically all the time. I have since removed said Dwarf's to another tank (except for one female i just couldnt catch) and added some young GBR's.

Now these seem to be doing the same thing. Gasping at the surface for air. All the other fish seem fine.

Any ideas about what I am doing wrong?

I do have bugger all surface agitation as the outputs for my external fluvial 205 filter are about an inch below the water surface.

Will me adding a truckload of foreground plants help with the O2 levels in the tank? Thereby preventing the Cichlids gasping?

Are my CO2 levels set realistically for my tank setup?

The rest of my param's are fine and the tank is now almost 5 months setup with these issues just occuring with the addiiton of CO2.

Though i only have my lights on for 8 hours a day. This could be upped to 10.

One other thing I thought of doing to increase the surface agitation would be add a small HOB filter (without medium atm) that I have kicking about. To off gas more CO2. But in my mind it kind of defeats the point in adding more CO2 in the first place.

Any advice appreciated.

Best Regards,

John

 

[Purrbox]

Some surface aggitation is actually a good thing in a planted tank even with CO2 injection. You want to aim for a slight ripple across the surface. While this will cause some CO2 loss it will also improve the O2 levels at the same time. Since you are using Pressurized CO2 this is easily compensated for by your setup and will only cause you to use CO2 slightly faster. It should help with the issues you are seeing with the fish. The other option would be to run a airstone at night to help increase O2 levels when both the plants and fish are using O2.

 

[HiJaC]

Some surface aggitation is actually a good thing in a planted tank even with CO2 injection. You want to aim for a slight ripple across the surface. While this will cause some CO2 loss it will also improve the O2 levels at the same time. Since you are using Pressurized CO2 this is easily compensated for by your setup and will only cause you to use CO2 slightly faster. It should help with the issues you are seeing with the fish. The other option would be to run a airstone at night to help increase O2 levels when both the plants and fish are using O2.

Thanks! I'll hook up the spare small HOB filter tonight and have it spray across the surface.

John

 

[HiJaC]

Hi,

Just to update. Stuck my old HOB filter without any medium in the tank last night when the PH was sitting at 6.74 (after a full 8 hours of light).

Instead of the tank dropping down to 6.66 by the morning it was sitting happy at 6.77. When the lights come on the CO2 should kick in again to keep it at 6.8.

No GBR's at the surface and the fish seem alot more lively.

Happy John.

Well except for the fact i can't quiet get the filter plug down the back of the tank, but thats a problem for the rest of the day.

Another bonus is I can stick in spare filter material in the little HOB filter to run it in for any extra tanks i'll be needing.

Thanks again,

John

 

[Purrbox]

Sounds great. Glad that it worked for you!