I have to disagree with the above statement.
In my planted 55G (4 watts/gal, pressurized CO2, pH 6.8-7.0; GH 7; KH3) my pH only changes about 0.2 points from day (CO2 on) to night (CO2 off).
Co2...24/7 or not?
- Thread starter jmarsh3253
- Start date
I have to disagree with the above statement.
In my planted 55G (4 watts/gal, pressurized CO2, pH 6.8-7.0; GH 7; KH3) my pH only changes about 0.2 points from day (CO2 on) to night (CO2 off).
What a lot of people refer to as pH shock is actually osmotic shock. That's why CO2 pH swings aren't harmful but KH(baking soda) and TDS induced pH swings are. It's the osmotic pressure change that kills the fish.
I think the strongest argument in favor of turning CO2 off at night is fish health.
While we cannot vary NO3, PO4, NH4 etc, we can rapidly change the CO2.
Does anyone here believe (honestly) that 1 ppm of CO2 is worst, than 30ppm of CO2 to fish?
CO2 is a "pollutant" and a toxin, much more so than NO3(but not even close to that of NH4), yet we add it without issue.
Some bicker about higher NO3 levels however even though CO2 is the cause of far more fish death, no one has killed their fish using KNO3 to date that I've heard of.
Fish use a lot of energy to respire.
This is a two edge sword, why?
Fish respire CO2 and take up O2.
It's not just about O2 alone nor CO2 alone.
It's both.
When we have the day light and high CO2, that's fine because the plants are producing a lot of O2.
At night?
No!
So towards the dawn, you have the lowest O2 levels and the highest CO2 if you use 24/7.
This is radically more important than pH swings which have no bearing on fish health in terms of CO2 enrichment. If so, we could not do massive water changes without adding CO2 back to the replacement water...........which almost no one does. Folks have been doing large water changes on planted tanks for many decades and use CO2 also, so clearly my fish are not dead, so I have a hard time accepting the notion that pH swings due solely to CO2 are any concerned for fish, you need to prove decades and 1000's of tank's worth of observations to explain that one away!
Which clearly folks are not going to be able to do.
So..........we are left with that it does not matter nor help.
It's(24/7) a simpler method for many folks, and if you do not add enough or have a lower flow tank, then perhaps you need to have a full CO2 enrichment when the lights come on to start with, but if you focus on adding a more responsive CO2 system to begin with, there's no need.
Fish do not do as good with high CO2 and lower O2.
They do okay with high CO2/highO2.
They do well with high O2 and low CO2.
So it's two things.
If you have issues adding CO2:
Add more surface movement, enough to see the water moving but not enough to break the surface.
Will you lose some CO2?
Yes.
But it's cheap and adding more is simple, turn the knob another 1/4 turn:grinyes:
What do you gain?
Well, more O2 at night when you need it.
Better circulation/more flow.
Better bacteria conversion of waste(they use O2 as well).
Clearer tank.
You can also help by having plenty of good current in the tank as well as having lots of flow through CO2 reactor(more is better until you start degassing the unit). Or good flow by a disc so that the mist gets well distributed throughout the entire tank.
A pH/KH drop checker can also help a great deal and makes monitoring CO2 much easier.
http://www.barrreport.com/estimative-index/2818-drop-checkers-co2-indicators-why-how.html
I like CO2 mist methods which you can check here:
http://www.barrreport.com/co2-aquat...otes-co2-mist-methods.html?highlight=CO2+mist
Basically blasting CO2 mist before it can fully dissolve into the plant beds.
Gas froth CO2 essentially.
As the plants grow and fill in, the flow and current dropos dramatically, by about 3-10X. you need to either add more current or kept the plants well pruned, slower growth, (less light etc will do that), chose slower growing species etc, or prune a lot more.
All these things influence CO2, O2 and fish health.
They are interwoven so while you might want to isolate things, you will also want to consider what else might be happening.
Regards,
Tom Barr
While we cannot vary NO3, PO4, NH4 etc, we can rapidly change the CO2.
Does anyone here believe (honestly) that 1 ppm of CO2 is worst, than 30ppm of CO2 to fish?
CO2 is a "pollutant" and a toxin, much more so than NO3(but not even close to that of NH4), yet we add it without issue.
Some bicker about higher NO3 levels however even though CO2 is the cause of far more fish death, no one has killed their fish using KNO3 to date that I've heard of.
Fish use a lot of energy to respire.
This is a two edge sword, why?
Fish respire CO2 and take up O2.
It's not just about O2 alone nor CO2 alone.
It's both.
When we have the day light and high CO2, that's fine because the plants are producing a lot of O2.
At night?
No!
So towards the dawn, you have the lowest O2 levels and the highest CO2 if you use 24/7.
This is radically more important than pH swings which have no bearing on fish health in terms of CO2 enrichment. If so, we could not do massive water changes without adding CO2 back to the replacement water...........which almost no one does. Folks have been doing large water changes on planted tanks for many decades and use CO2 also, so clearly my fish are not dead, so I have a hard time accepting the notion that pH swings due solely to CO2 are any concerned for fish, you need to prove decades and 1000's of tank's worth of observations to explain that one away!
Which clearly folks are not going to be able to do.
So..........we are left with that it does not matter nor help.
It's(24/7) a simpler method for many folks, and if you do not add enough or have a lower flow tank, then perhaps you need to have a full CO2 enrichment when the lights come on to start with, but if you focus on adding a more responsive CO2 system to begin with, there's no need.
Fish do not do as good with high CO2 and lower O2.
They do okay with high CO2/highO2.
They do well with high O2 and low CO2.
So it's two things.
If you have issues adding CO2:
Add more surface movement, enough to see the water moving but not enough to break the surface.
Will you lose some CO2?
Yes.
But it's cheap and adding more is simple, turn the knob another 1/4 turn:grinyes:
What do you gain?
Well, more O2 at night when you need it.
Better circulation/more flow.
Better bacteria conversion of waste(they use O2 as well).
Clearer tank.
You can also help by having plenty of good current in the tank as well as having lots of flow through CO2 reactor(more is better until you start degassing the unit). Or good flow by a disc so that the mist gets well distributed throughout the entire tank.
A pH/KH drop checker can also help a great deal and makes monitoring CO2 much easier.
http://www.barrreport.com/estimative-index/2818-drop-checkers-co2-indicators-why-how.html
I like CO2 mist methods which you can check here:
http://www.barrreport.com/co2-aquat...otes-co2-mist-methods.html?highlight=CO2+mist
Basically blasting CO2 mist before it can fully dissolve into the plant beds.
Gas froth CO2 essentially.
As the plants grow and fill in, the flow and current dropos dramatically, by about 3-10X. you need to either add more current or kept the plants well pruned, slower growth, (less light etc will do that), chose slower growing species etc, or prune a lot more.
All these things influence CO2, O2 and fish health.
They are interwoven so while you might want to isolate things, you will also want to consider what else might be happening.
Regards,
Tom Barr
