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[APD] Re: CO2 levels

> From: "Beek, Graham" <Graham_Beek at ds-s.com>
> Is there a standard level of C02 for a body of water
> with no injection at a specific temperature?

Theoretical CO2 equilibrium at sea level and 75 F is 0.498 mg/l. An
aquarium with fish and typical bacteria will run 1.5 to 3 mg/l due to
respiration. A higher bioload will, of course, add more CO2.

The accuracy of your pH or KH reading from the chart will be affected by
the resolution of your test kit. A LaMotte Alkalinity test kit is good for
2-3 mg/l (around 0.15 dKH) where a Tetra KH test kit may be only good for
8 mg/l (around 0.5 dKH). With low levels of CO2, the error band will be
quite large. pH test kits are usually more accurate for this type of
thing. YMMV

> From what I've read before other factors influence the chart
> such as phosphates, tannic acids from bogwood etc. Is the chart that
> reliable in a real tank scenario?

Here's an example: if you have low levels of phosphate, the chart will be
close enough. If you have higher levels of phosphate, it will not be
accurate. If you are adding pH adjusting compounds in a large enough
quantity to adjust the pH, that is enough to throw the chart out of whack.

If you are going to make adjustments based on what you measure, you would
be better off directly measuring what you are interested in. KH and pH
test kits aren't particulary expensive. You may do damamge adjusting
parameters based on marginal measurements.

If this is just a curiousity thing, yeah, the charts are fine.

George Booth in Ft. Collins, CO (gbooth at frii dot com)
 The website for Aquatic Gardeners by Aquatic Gardeners
   http://aquaticconcepts.thekrib.com/  (mirror)

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