GlassWalker
Member
I installed a drop checker not that long ago... and decided I hate it already. Well, I know I don't have enough CO2 until I install a better diffuser, but looking at a blue-green colour and watching it change to a slightly greener blue-green isn't exactly telling me much.
I'm aware that calculation of CO2 from pH and KH has difficulties due to other substances altering pH in tank water, plus not knowing the actual KH accurately.
I thought about the a variation of the drop checker but replacing the indicator with an pH probe, on a cheaper scale than the one proposed by plantbrain. That lead me to the thought, couldn't we work out the effective KH of the tank?
My proposed method is as follows:
Take a reference 4 dKH solution (or similar)
Take a sample of tank water
Put both into separate open containers and allow them to reach CO2 equilibrium with the air. Temperature may have an effect, so it may be best to do this at tank temperature.
Measure the pH of the 4 dKH solution. Use this to calculate the CO2 it has reached.
Measure the pH of the tank water sample. Knowing the CO2 above, calculate back to KH.
From then, you can use that KH value for CO2 calculations.
Probable weaknesses:
This is not a measurement of KH, as it still includes other factors that influence pH
I don't know if this effective KH value scales with other pH altering substances in water. I would assume it doesn't, and the question then becomes, how much error is there?
Tank water is unlikely to remain stable in this measure. Question is, how much change is there likely to be? This process may need to be repeated regularly. For starters I might try this before and after a water change.
Any thoughts?
I'm aware that calculation of CO2 from pH and KH has difficulties due to other substances altering pH in tank water, plus not knowing the actual KH accurately.
I thought about the a variation of the drop checker but replacing the indicator with an pH probe, on a cheaper scale than the one proposed by plantbrain. That lead me to the thought, couldn't we work out the effective KH of the tank?
My proposed method is as follows:
Take a reference 4 dKH solution (or similar)
Take a sample of tank water
Put both into separate open containers and allow them to reach CO2 equilibrium with the air. Temperature may have an effect, so it may be best to do this at tank temperature.
Measure the pH of the 4 dKH solution. Use this to calculate the CO2 it has reached.
Measure the pH of the tank water sample. Knowing the CO2 above, calculate back to KH.
From then, you can use that KH value for CO2 calculations.
Probable weaknesses:
This is not a measurement of KH, as it still includes other factors that influence pH
I don't know if this effective KH value scales with other pH altering substances in water. I would assume it doesn't, and the question then becomes, how much error is there?
Tank water is unlikely to remain stable in this measure. Question is, how much change is there likely to be? This process may need to be repeated regularly. For starters I might try this before and after a water change.
Any thoughts?