im having trouble reading kh result

[_newbie_]

i have a table that uses kh and ph to estimate co2.

i just bought a JBL KH Test Set. step 4 of the instructions reads: one drop of reagent solution used corresponds to 1 degree carbonate hardess (German scale).

it took 3 drops to change color. does this mean the kh is 3? may seem like a really stupid question, but if you dont know....

please help.

 

[blue_soda025]

Yes, that is correct.

 

[_newbie_]

thanks for the simple answer. feeling a little sheepish but better safe than sorry. does the following seem ok?

planted coldwater 14g
fishless
NO2 0 ppm
NO3 0 ppm
NH3 0.5 ppm
ph 6 (lowest reading possible with kit)
kh 3
CO2 87 ppm (est)
DIY jello CO2 injection ( : blackcurrent : )
light 2-3wpg (depends how what kind of g)

 

[plah831]

are you planning on keeping it fishless, or do you want to add fish? If you don't have animal life in there, you definitely have a lot more leeway to play with CO2, fertilizers, etc. A KH of 3 degrees should be just fine If your carbonate hardness were less than 3, then you would experience large pH swings because the carbonate is a natural buffer to resist the acidity from added CO2.

Is your pH 6.0 before CO2, or after? If it's that low BEFORE the addition of carbon dioxide, then you might be in trouble. If that's the reading after, I think it's OK.

 

[iktomiwicasa]

Fish?

Do you plan to stock it with fish? CO2 @87ppm is unsafe for them. Target for a fish tank is 20-ish ppm CO2 or a bit higher I believe. Maybe one of the CO2/plant experts will chime in here

 

[plah831]

Right. Anything above 35 ppm is considered potentially lethal to fish.
see this chart http://www.aquamaniacs.net/co2.html
10-25 ppm is ideal. I don't think you could even get 87 ppm with DIY CO2! Unless it was a tiny 1 gal bowl or something

 

[_newbie_]

ph before CO2 is 7.0

i was thinking of leavivng it fishless for the moment while i experiment with plants, hardscape, CO2, kh, ferts, lightning, etc.

maybe the CO2 isnt 87ppm the chart just said kh 3 x ph 6.0 = CO2 87

 

[_newbie_]

another chart reads 90 ppm.... will check a few more charts just to be sure lol

 

[plah831]

The relationship is not a simple multiplication one. See the chart I listed above, as well as this graph http://www.thekrib.com/Plants/CO2/kh-ph-co2-chart.html

There is a calculator on this page http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm
The last page also has the mathematical formula for the relationship between KH/pH/CO2 as "The formula used for this calculation is: CO2 (in PPM) = 3 * KH * 10^( 7-pH ) where KH is Carbonate Hardness in degrees."

 

[_newbie_]

i think i might drop the flourish excel and start experimenting with flourish potassium, nitrogen, phosphorus and trace.