CO2 Calculator

[jarrod0987]

I am experimenting with a Walstad tank. She states the soil provides enough CO2 for low and medium light tanks etc.

She also states the plants can switch to using Bicarbonate instead if CO2 is depleted. None of my plants have melted this month so this must be what is going on.

I don't inject CO2. I have some Excel but I don't use it.

Ph is 8.00 (Phep 5)
KH is 7.75 dkh (API)

Online calculator says that's 2.353 CO2 which is very low.
Target is 15-30 ppm.
Light has been off for 9 hours so it should be accumulated now.
I do have 1 ppm ish of phosphate which the calculator says can cause errors in the calculation. Is this calculator worth anything?
I know this is a high tech tank community for the most part and injection is the favorite way. I just want to know of the calculator is worth anything. I see most of you like drop checkers instead.

Thanks for any input.

 

[philipraposo198]

Using the chart is IMO the most accurate way when combined with a ph probe.

The numbers your are seeing seem right too me. You can maintain low light plants with that concentration but growth will be slower than with 30ppm co2.

If my non injected tank I have loads of plants. My largest is a huge clump of water sprite. During peak hours once the light has been on for a bit my co2 levels in that tank are non existent. The plants use it all up.

 

[jarrod0987]

Using the chart is IMO the most accurate way when combined with a ph probe.

The numbers your are seeing seem right too me. You can maintain low light plants with that concentration but growth will be slower than with 30ppm co2.

If my non injected tank I have loads of plants. My largest is a huge clump of water sprite. During peak hours once the light has been on for a bit my co2 levels in that tank are non existent. The plants use it all up.

Awesome, thanks. Does anybody know how much of an error phosphate causes? Perhaps there is an advanced calculator out there somewhere?
I'm really surprised to hear 2 ppm is the norm for a low tech tank. Fascinating

I don't mind about slow growth. This is a low maintenance experiment.

 

[Caliban07]

First off is like to just mention that not all plants can use bicarbonates. Those that can't will most likely be out competed after a time and the species that are and are not able to do this are listed in her book

Also the chart is based on a hypothetical scientific calculation and can't really be used to any degree of accuracy. The values given in the chart are based on an assumption that the only influence on the ph value is carbonic acid. Nothing else. In our aquariums there are too many other acids, alkalines and buffers influencing the ph. This is why people you a drop checker.

A drop checker is basically a pH test, but not for your tank water. It measures the pH of your drop checker solution, which indicates CO2 levels. How it works is there is an enclosed air chamber trapped between the tank water and the drop checker liquid. The CO2 in your tank will flow freely into the trapped air, and then in to the drop checker compartment. It will do this until the water in the tank and the water in the drop checker reach equilibrium. This means that there is equal concentrations of CO2 in both chambers of liquid. CO2 is the only variable effecting the pH in the drop checker, therefore pH in the drop checker is directly related to CO2 levels in the tank.

The solution is a know value of dkh that the ph solution works with to achieve a certain colour. Only issue with drop checkers is the these are also listed as an approximation on their own boxes and the value is not real time.


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