CO2 measurement in alkaline water

[Elyse]

Hey everyone, I've been thinking of trying CO2 for my planted aquariums to get some harder to grow plants going. I tried to measure my baseline CO2 levels to see how much CO2 I really would need but the reading said greater than 50 in all my aquariums and tap water. On my CO2 test it said *alkaline water may affect the accuracy of the test. The pH in my tanks floats around 7.35.

So is my CO2 really greater than 50, if it is can I just increase my lighting?

Or will I not be able to get an accurate CO2 reading until my pH is acidic?

[Marcelo]

Hi Elyse, what do you mean with 50? And how are you measuring this number ?

When you say you are trying CO2, are you saying you have a tank with injected CO2?
 

marcelo

 

Edited October 17, 2023 by Marcelo

[Elyse]

On 10/16/2023 at 10:24 PM, Marcelo said:

Hi Elyse, what do you mean with 50? And how are you measuring this number ?

When you say you are trying CO2, are you saying you have a tank with injected CO2?
 

marcelo

 

50 mg/l

I use an ex aqua photometer to measure all of my water parameters. Definitely more fire power than I need but I love the chemistry behind it.

I am trying to measure my CO2 levels WITHOUT injected CO2 to see if I even need to inject C02 or if there are other variables that may be my limiting factor such as light intensity.

[nabokovfan87]

There is a KH:PH chart that gives you a dissolved co2 level as a result.  (From Tom Barr)

I would start there as a sort of check on the value you're measuring and see if things are close.  As always, if you have a question when it comes to a test, just try to verify it with a secondary test somehow.

[Elyse]

On 10/16/2023 at 11:26 PM, nabokovfan87 said:

There is a KH:PH chart that gives you a dissolved co2 level as a result.  (From Tom Barr)

I would start there as a sort of check on the value you're measuring and see if things are close.  As always, if you have a question when it comes to a test, just try to verify it with a secondary test somehow.

I found it, this was super helpful...thank you!

[Marcelo]

I would suggest you to search this forum for “siesta” - you will love that article.