Too much CO2?

[necigrad]

I've been playing with my CO2 setup a bit and I think I've got too much CO2 in the water. The system itself is the Nutrafin system, which I believe is also the Hagen system, just rebranded, and it's on a 24G. Using my own mix (packets were expired) of 1t yeast with water and suger as instructions specify, I'm getting a pH of 6.8, and that's only at 10:30 at night. According to the chart on Rex Griggs site, with a KH of 10, that's dangerous. It works out to a CO2 level of 47.5ppm. Should I use even less yeast? I've already set the diffuser to it's lowest level, which is the highest up, leading to less time on the diffuser. Would a valve of some type, or a solenoid work? I'm concerned about that because I don't know that the container could withstand tthe pressure. Since I just adjusted the mix this morning I don't know what it will be like during the day, but right now going into nighttime it's increasing CO2 levels.

[Rex Grigg]

In a yeast based system no how much yeast you start with you will reach a point where you end up with as much yeast as the system can support.

Many people don't understand that yeast is alive. And it reproduces. And it will reproduce as long as the conditions are favorable to reproduction.

Now I have no idea how fast any given yeast reproduces. But let's say it is ½ hour.

You start with one yeast at 12:00

12:00 1
12:30 2
1:00 4

and so on.

Now if you started with 4 yeast at 12:00 you are only going to shave 1 hour off the final total.

In short there is no way to control the CO2 production in a yeast based CO2 system other than........temperature. Warmer = more CO2. Colder = less CO2.


Also the pH/kH/CO2 chart is based on the fact that the ONLY thing lowering the pH is CO2. Wood or peat in the water column will affect the chart. Also it's based on the only buffer in the system being bicarbonates.

And with consumer level test kits you can be off by up to 0.5° in pH and kH. And that makes a difference.

If you fish are not acting stressed don't sweat it.

[necigrad]

My first runthrough where I dumped in a whole packet of yeast (yeah, whoops) I came home in the morning to find all my rasboras slurping at the top, and none of the fish wanted to eat. I noticed two rasboras doing this again last night. I pulled the hose off of the canister, and just plugged it back in now. I'll probably cut it down to 1/4t sometime and see what happens. OTOH, my plants don't seem to be doing well, so it may not be relevant. I want to give them a few days to see what happens before I get concerned though.

[tinkerman]

I have a yeast co2 system and have found that you can control it too a point. I'm using a 1 gal gas can and a gang valve I got from wal-mart. the gang valve is clear with 2 knobs. I have done some modifacation to this like taking all peices apart that can and super glueing them togetter and taking the knobs out and putting teflon tape on them. I can control the amount of bubbles that come out too quite precition although still playing with yeast recipe yet. Tring the powerhead/gravel vac diffusor right now and take alot of pressure, but with gas can, bubble counter, gang valve, and power head for diffusor it is very easy to control.

[ChicoRaton]

My first runthrough where I dumped in a whole packet of yeast (yeah, whoops) I came home in the morning to find all my rasboras slurping at the top, and none of the fish wanted to eat. I noticed two rasboras doing this again last night. I pulled the hose off of the canister, and just plugged it back in now. I'll probably cut it down to 1/4t sometime and see what happens.

re-read this, necigrad.:




In a yeast based system no how much yeast you start with you will reach a point where you end up with as much yeast as the system can support.

Many people don't understand that yeast is alive. And it reproduces. And it will reproduce as long as the conditions are favorable to reproduction.

Now I have no idea how fast any given yeast reproduces. But let's say it is ½ hour.

You start with one yeast at 12:00

12:00 1
12:30 2
1:00 4

and so on.

Now if you started with 4 yeast at 12:00 you are only going to shave 1 hour off the final total.

In short there is no way to control the CO2 production in a yeast based CO2 system other than........temperature. Warmer = more CO2. Colder = less CO2.

Changing the amount of yeast affects how quickly the bottle ramps up to maximum production, but doesn't change the amount of the maximum production. If you can't change the temperature of the bottle, add an airstone or some other way of increasing surface agitation, so that some of the excess CO2 being produced get gassed off into the air.

[necigrad]

Yeah, I realised that after I posted and kinda hoped my error would be overlooked. I'll probably add an airstone and pump then sometime. I just tested the water and the pH is at 7.0. I think that's probably about right, so I'll put the airpump on time opposite the lights. Thanks for the help.

[ChicoRaton]

no prob. You might want to add a valve behind the airstone and start slow, because I don't think your plants are using THAT much CO2 during the day, considering your low light and lightly planted tank. Having an airstone on full blast only at night might cause some big pH fluctuations. Good Luck :-)