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#### GDominy

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#### masYPSI

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How do you convert from degs, on the chart, to ppm, what i have.

#### Lycosa

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Divide ppm by 17.8 to get degrees.

#### west9491

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you don't have to convert, skip the degrees part. Type in your pH, then skip the degrees box, type in your KH reading ppm in the box to the right. Then when you click on the degrees box, your reading of both your co2 concentration and KH reading converted to degrees should show, pretty neat, took me a while to fig. out.

but i'm running 16.6 w/ DIY co2, i have the stuff for a co 2 tank, just can't find a co2 tank that is ridiculously priced, any suggestions?

#### cbennett

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just a note: most KH test kits give results in "mg/L" - that is the same as ppm.

#### leoslizards

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just a note: most KH test kits give results in "mg/L" - that is the same as ppm.
Yeah I was wondering the same thing. This has been very confusing to me. My test kit also give results in "mg/L" and I don't know how to measure that in ppm. For example my test kit says to add one drop of solution at a time until it turns a certain color and take the number of solution drops added and multiply it by 20 for GH and 10 for KH. My tests resulted in 11 drops of GH solution and 11 drops of KH solution, which I then multiplied.

11x20=220 GH
11x10=110 KH

The chart only goes to 15 KH Can someone please explain this to me? Thanks.

#### Hoppy

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The chart is based on degrees KH, not KH in ppm or mg/liter. The conversion factor is 17.86 ppm per dKH. Your 110 KH = 6 dKH.

#### IceH2O

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Goes to show these charts and caculators are worthless.

I don't inject CO2, I use Excel which won't translate into a CO2 reading.

According to the chart my CO2 level is almost 38 ppm.

We all know thats impossible. Most I could have is whats in the atmosphere, what is it 3-4 ppm?

#### Hoppy

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The charts and calculators are not at all worthless. They are very good, but not for determining from the tank water KH and pH what the CO2 concentration is. If you use a drop checker, with distilled water having a known KH in it, the chart and calculator work extremely well. If you read carefully, Chuck Gadd notes in his discussion that the equation is not valid for water that isn't "perfect".

#### Glouglou

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And

It’s for that some people prefer to use a drop checker solution, where you mix ph reagent and distill water that you bring to 4 or 5 dkh.

This way, no more guess...

4 dkh green at 30 ppm CO2
5 dkh green at 40 ppm CO2

cool
:icon_mrgr

#### plantbrain

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Oh, there is certainly guessing, but it's trying to figure out how long the reaction time and what color is what in the drop checker.

Still, vast improvement over other methods folks had been using and assuming about KH.

Regards,
Tom Barr

#### BlueRam

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We all know thats impossible. Most I could have is whats in the atmosphere, what is it 3-4 ppm?
Atmosphere ~ 300 ppm (0.3%)
Water at equilibrium ~2-5 ppm.

#### Darth Sensei

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According to that chart, my baseline CO2 levels are only 1.8. Is that possible?

My pH is 8.0 right now and 6 degrees KH.

IF this is correct, what ph should I shoot for? My calculation shows 6.8.

#### Rex Grigg

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That is possible.

And you should shoot for a a drop in pH of one degree. So 6.8-7.0 is correct.

#### Steve Z

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What does the Kh mean on Chuck's chart

#### efish

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so is this really needed for DIY CO2? Good thing I wasted the money on a kH and gH tester.

#### CmLaracy

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according to this I have over 100 ppm CO2 in my tank....

I have a KH of 3.5, and a pH that drops down, BELOW 6. I don't have any fish in the tank, and I'm using an ADA diffuser at 3bps in a 42 gallon.... My GH is also at .5

Is my CO2 really at over 100ppms?

#### Homer_Simpson

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according to this I have over 100 ppm CO2 in my tank....

I have a KH of 3.5, and a pH that drops down, BELOW 6. I don't have any fish in the tank, and I'm using an ADA diffuser at 3bps in a 42 gallon.... My GH is also at .5

Is my CO2 really at over 100ppms?
Hmmm.....interesting, I guess different KH and PH readings can cause wide fluctuations to the point where the readings may or may not be accurate. I have a 10 gallon where water parameters tested monthly over 6 months would suggest that water parameters would be in the range considered ideal for plant growth, but the tank was plagued by fish deaths and very poor plant growth. As per drop checker the c02 level was 30 ppm, but as per on-line chart it was only 11.7 ppm. In that case, I was more inclined to believe that the on-line chart was more accurate, since black brush algae was one of the first types of algae to materialize and this usually materializes when
c02 levels are suboptimal.

#### poptarts356

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how long will a 20lb co2 tank last for aprox. to get good levels in a 200gal tank? any good guesses

#### wkndracer

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how long will a 20lb co2 tank last for aprox. to get good levels in a 200gal tank? any good guesses[/quote

Running off the same cylinder (20lb) feeding two 75g tanks for over 6 months without any pressure drop. Drop checker color green/yellow green through Rex style reactors using AM controllers.

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