KH and CO2

[TheRealJ0ckel]

Using this chart I calculated the CO2 in my tapwater.  My KH is off the charts (test strips) while my pH is pretty low. The only reason I could think of was high CO2 since CO2 lowers the pH and hightens the capacity of carbonates in the water.

My question is wether this CO2 is available for my plants and wether it might harm my fish. I don't have any problems with my fish right now, but they are all pretty hardy. I do get  a lot of growth, even on my anubias, though my java moss struggles.

[BaRanchik]

The dissolved CO2 does help your plants, and I wouldn't be too concerned if your fish are doing well as is.
Keep in mind that the tap water holds lots of CO2 when it's first put into the tank, but plants use it all the time.

Anyway, changing stuff around too quickly can only do worse, so if you want to raise pH or something similar, make sure you do it slowly.

[Mmiller2001]

On 5/12/2021 at 2:41 AM, TheRealJ0ckel said:

Using this chart I calculated the CO2 in my tapwater.  My KH is off the charts (test strips) while my pH is pretty low. The only reason I could think of was high CO2 since CO2 lowers the pH and hightens the capacity of carbonates in the water.

My question is wether this CO2 is available for my plants and wether it might harm my fish. I don't have any problems with my fish right now, but they are all pretty hardy. I do get  a lot of growth, even on my anubias, though my java moss struggles.

What ppm CO2 is the chart showing for your tap water?

[TheRealJ0ckel]

Somewhere between 90 and 70 mg/l (way to high according to the table)

[Mmiller2001]

2 hours ago, TheRealJ0ckel said:

Somewhere between 90 and 70 mg/l (way to high according to the table)

If you are not changing a significant amount of water percentage; I think you will have no problem with fish. By significant, 70 to 80%. If you are worried, fill a bucket and let it sit for 24 hours. A good chunk of CO2 will gas off.

[TheRealJ0ckel]

Are you sure the CO2 will gas out? It's been in the tank for two weeks since the last major water change with a sponge filter and it hasn't really changed.

[Mmiller2001]

8 minutes ago, TheRealJ0ckel said:

Are you sure the CO2 will gas out? It's been in the tank for two weeks since the last major water change with a sponge filter and it hasn't really changed.

100% Sounds like something else is going on. Are you getting the 70-90ppm from your tank water or from the tap water?

[laritheloud]

On 5/12/2021 at 4:41 AM, TheRealJ0ckel said:

Using this chart I calculated the CO2 in my tapwater.  My KH is off the charts (test strips) while my pH is pretty low. The only reason I could think of was high CO2 since CO2 lowers the pH and hightens the capacity of carbonates in the water.

My question is wether this CO2 is available for my plants and wether it might harm my fish. I don't have any problems with my fish right now, but they are all pretty hardy. I do get  a lot of growth, even on my anubias, though my java moss struggles.

Am I understanding you correctly that you're not injecting CO2? Because if you're not, most sites will say the following:

 

Quote

NOTE: If you aren't adding CO2 to your water, and the CO2 level based on the pH and KH indicates more than 5ppm, then it is very likely that some other buffer (such as phosphate) is present in your water. In an inhabited aquarium, the amount of CO2 produced by the fish will not have an effect on CO2 levels in the water. Any excess CO2 created by fish will dissipate into the air, leaving a fairly constant CO2 level of about 3-4ppm. If you test your pH and KH, and without adding any CO2, the chart says you've got 20ppm CO2, don't believe it.

from the following site: https://aquariumplants.com/getting-your-co2-levels-right-goes-over-the-kh-ph-co2-relationship-myths-and-facts/

[StephenP2003]

Other possibility is misreading the strips, which I've done from time to time!