Need Help working out current CO2 level

[Vivienne]

Before I start adding CO2 to the tank I'd like to know what my current level is. The ph in the tank is currently 7.5 (Straight out of the tap it's 6.5/7) I just had a nutrfin kit and a KH/GH test kit delivered today. It's giving me a GH of 60 mg/l or ppm and a KH pf 20mg/L or ppm.

Is the KH on the CO2 chart in ppm/mg/l too ? If so, I calculate that my current CO2 level is in the region of 24 which isn't too bad and suggests I perhaps don't need to add CO2 right now. However, I know my water here is very soft. Am I a factor of 10 out when I'm reading the KH off the chart. Should I be reading along the line 2.0 rather than 20.0. That would give me CO2 of about 2.4 - very low.

Also I've heard mention of injecting CO2 causing a ph crash ? Could someone tell me a little more about this. With very soft tap water am I in danger of this ? How and why exactly does it happen ? - I assume the effect could be catastrophic.

Thanks in advance

 

[kenneth_kpe]

umm kh for the charts are usually in deg kh but there are charts using both, check out the online c02 calculator from chucks planted aquaria pages hope this helps

and yes.. c02 can effect the ph of your water, its all in the site just read around... o ya google it... loss the link and my pc' is acting up so i cant search it for you now

 

[Vivienne]

Thanks, All the charts I can find are in KH degrees.

I've spotted a small bit in the test booklet about convesion factors. mg/L to degrees hardness is 1 to dH degrees(orgH degrees), it's 0.056, to Clark H degree it's 0.07 and to fH degrees it's o.1 !!

Which one do I want ?

I can't be the only one with a test kit that gives results in mg/l or ppm.

 

[@ombomb]

This one has both measurements:

http/www.csd.net/~cgadd/aqua/art_plant_co2chart.htm

 

[RYO]

My test kit is in ppm. 1 drop =17.9ppmkh or 1dkh. just divide your result by 17.9 to get the dkh
Heres a link to work out you co2 content, all you need is you ph and kh levels
http/www.aquarix.com/en/co2calc.asp
If you tap water is 6.5 and you tank water is 7.5 somthing is uping the ph, most planted tanks tend to go the other way.
Just double check your readings.
Hope this helps

 

[Vivienne]

Brilliant, Thank you. I know exactly where I am now !

RYO - you're right that something's up. The increase in ph just now will could be a combination of two factors. I'm about 4 weeks into a fishless cycle at the moment so the addition of ammonia may be one factor. I'm adding 60 drops a day so I guess it will rise each morning when I add the drops and then gradually go down as it's converted to nitrite. (I don't know what effect elevated nitrite & nitrate levels have on ph.)

The other thing that may still be causing some residual effect is the DIY cement/styrofoam background in the tank. I know that that causes very high ph as the cement cures. It's been in place for nearly 6 weeks now, during which time the ph in the tank has dropped from in excess of 9.5 so it's come a long way ! It ought to have cured by now. I did about a 75% water change yeaterday, but I guess it's gonna take a few more before it stabilises to the same level as the tap water.

Because there are no fish in the tank yet to worry about, I guess I'll add the CO2 and keep monitoring the ph to see how far it drops. I'd prefer not to start adding bicarb or shells if it can be avoided. What's the mimimum I should let the tank ph get to ?

Incidentally, right now there's only one plant in the tank right now - an anubias attached to a piece of bogwood. When the other plants started to show signs of rotting (probably the very high ph, per another thread) I took them out and stuck them into a separate plastic container (where they're starting to produce new shoots although still looking in a rather sorry state). What will be the effect of adding CO2 to an underplanted tank ?

 

[RYO]

What will be the effect of adding CO2 to an underplanted tank ?

i would assume the ph would drop if the co2 isnt used