# How much CO2 to combat BBA algae?



## robitreef (Jan 4, 2005)

I just started up my pressurized CO2 system. I started out slow (1 bubble per second). I have 110W over a 75 that are on for 10 hours. I tested my nitrates and they were really high (200ppm)-probably because I was dosing too much KNO3. I stopped fertilizing for the moment and did a water change.
Tap probably has enough for now.

Anyway, should I increase the CO2? I am just using the glass diffuser and the fine mist of bubbles are directed into an inlet of a powerhead. I am still dosing Excel as well.


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## brad (Jul 10, 2005)

What are your co2 levels now? 30ppm is a good target. Bubble count isn`t a very good way to judge how much co2 your tank has. Too many other variables.


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## robitreef (Jan 4, 2005)

I will have to check. My pH before adding the Co2 was 7.5 and when I tested it last night it was at 7.0 I will have to test KH and then calculate the ppm of CO2. Thanks for the value to go by.


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## MatPat (Mar 22, 2004)

There has been some talk about CO2 levels lately and it seems the "new" method of determining CO2 levels is to take a sample of your tank water and let it sit out of the tank for 24 hours to degass. Read the pH of this sample and then adjust your CO2 so the tank's pH drops 1 point below this.

Example:

If your rested tank water pH is 7.4 you would want to increase your CO2 addition to the tank to drop the pH to about 6.4 This should give you about 30ppm.

Here is the link if you want to read more about the method:

http://www.aquaticplantcentral.com/...rtilizing/14281-another-co2-chart-to-try.html


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