The right CO2 level in your planted tank

[maverick786us]

This is the CO2 level in both my high tech tanks (CO2 drop checker in both the pictures) . My first tank is a small 37 Liter tank in which I have kept the bubble count 1 bubble per 3-4 seconds. My second tank is a 90L tank, in which the bubble counts per second is slight more than 1 bubble per second, that tank doesn't have live stock yet.

Both the tanks are using high end filters, Eheim Classic 250 in my 37L tank and Fluval 207 in my 89L tank. Both these filters seems to have very good flow rate that should provide enough surface agitation for gas exchange to take place. What I have read is if your filter has good flow, it will provide additional CO2 to your tank through gas exchange caused by surface agitation (besides pressurized CO2). The amount of CO2 that comes through the gas exchange is more than liquid carbon (glutaraldehyde) which I was initially using in my planted tank, when I was new into this hobby. I think the drop checker can only detect CO2 that comes from the CO2 kit, not from the Gas exchange or CO2 exhaled from fishes. Is my CO2 level sufficient for these plants or should I increase or decrease it?

 

[hypnogogia]

What I have read is if your filter has good flow, it will provide additional CO2 to your tank through gas exchange caused by surface agitation

This is not correct. Whilst surface agitation will increase gas exchange it will actually result in the injected CO2 leaving your water, rather than more CO2 being added. This is because the CO2 concentration with injected CO2 is higher than it would be when the CO2 in the water is equilibrium with the atmosphere. Surface agitation is, however, important to ensure adequate oxygenation of your water because you are injecting CO2.

I think the drop checker can only detect CO2 that comes from the CO2 kit

Incorrect. The drop checker actually actually indicates a doh change in the indicator solution because of the presence of CO2, irrespective of the source of that CO2. How would it tell which CO2 molecules come from injection and which form the atmosphere?

Is my CO2 level sufficient for these plants or should I increase or decrease it?

You are looking for your indictor solution to turn from blue to green. This will indicate an approximate 1pH drop, which equates to 30ppm of CO2. Having said that, not all plant will require 30ppm of CO2. I do not aim for a 1pH drop as the plants that I have do not require it.

 

[Connswater]

I don't get a commission from JBL, but I think this link is really helpful:

CO2

Why is CO2 so important for plant care? What benefits does CO2 fertilisation provide?

www.jbl.de

I certainly don't try to drop the pH by one, in fact I've had great success with low 24/7 CO2 and stable pH.

 

[simon_the_plant_nerd]

The amount of CO2 that comes through the gas exchange is more than liquid carbon (glutaraldehyde)

The CO2 that comes from gluteraldehyde is approximately nothing. The CO2 from surface agitation is going to also be approximately nothing.

 

[maverick786us]

Yes I realized that, and accepted the fact that a planted tank with grass needs pressurized CO2