Co2 Injection Is *lowering* Waters Co2 Content?

[jnms]

Hi, I am hoping you guys can help out with this question.

My tap water has a Kh of 17, and a Ph of 7.7 using the chart on MrAlgae's ( http/mralgae.blogspot.com/2008/01/water.html ) site, I worked out that my water therefore had a CO2 content of around 10ppm. As I am working on creating a heavily planted tank I thought it would be an idea to increase the CO2 content.

So, I set up a DIY CO2 injector, this has been running for around 10 days and the plants are doing really well.

Today I took the Kh measurements again and the Kh has dropped to 12, with the Ph remaining at 7.7

This now means my waters CO2 content is around 7ppm.

Injecting the CO2 reduces the Kh. When the Kh decreases so too does the waters CO2 content.

This seems a bit odd to me and I have to wonder if I am missing something?

So what's going on?

 

[aaronnorth]

if the kh drops then it should be easier to inject more CO2 more easily thus resulting in a drop in ph. Also if your water has a lot of buffereing capacity, then it can give inaccurate results, Drop checkers are more reliable.

 

[Mikaila31]

As aaronnorth suggested CO2 drop checkers are much easier to use and more accurate. The seller Aquaticmagic on ebay is a good place to get one fairly cheap. Ebay Item number: 260272123955

 

[jnms]

Thanks for your help guys!