hi, I just got my ph drop checker. to be true, this is not what I thought.
what I have is the glass "checker" (dont know how it's call), a cheap chart that tells me what colour match each ph level and a bottle of co2 test.
they say: add 5 drop of co2 test, add water from the aquarium up to the level (witch level).
I thought we use a know kh solution in these things? also, how mutch water for those 5 drop since there is no "level"?
How will I know what CO2 level there is in my thank with this ph chart? If I would have wanted to know what ph I have, I would have use way beter checker.
also, yes, the colour might change (did not over the last 45min) once Co2 from the tank make the colour change but what does it tells me?

thanks

You have to make the reference KH solution yourself. I would say fill the checker half way with KH reference solution and then add a few drops of the pH eeagent. Assuming a KH reference = 4 degrees, a green color would get you about 30ppm of CO2. The green color should coincide with a pH about 6.6 or 6.7.

thx for your help,
you say to add a few drop of ph reagent to it. does that meen the quantities of drop vs volume of kh solution is not important at all?
also, it will turn green yeah but how green? dark green, light green, etc? some test like nutrafin are bad like that. I'me trying to find lamotte test online and dont find any. would these test easier to read?
with tha drop cheker, there is that Co2 test reagent that comes with the cheap ph chart. should I use this? colours are easy to read (ph6=yellow, ph7=light green, ph8 = dark green, ph9 = pink, etc)
what is that Co2 test by the way? the device is sell to mesure ph that I see so it is a ph test?

Patrice, check out this thread making-standard-kh-solutions for how to make a solution to go in the drop checker.

Most reagents need about 2 drops per 1ml of water, although all that will happen if you add too much is that the colours are darker, so less makes them easier to read.

Basically, all a drop checker is, is a PH tester, but where it differs, is that over about 2 hours (roughly how much time they take to work) the CO2 passes from the tank water, through the air gap, and into the checker water, thus changing the PH of the test solution. This makes it much much more accurate, as all that can alter the PH of the test solution is gas, not substrate, ferts or any of the other things we throw in our tanks.

The reason we make our own KH solutions is that then we know EXACTLY the reading for that solution. As Shane says, a solution of 4 dKH will yield 30 ppm when it goes green, how dark/light that is depends on the reagent amounts you used. It just needs to be not blue, or blue/green.. if its green, your on the right track. Mine tends to go a bit yellowy if I really crank up the CO2.

As far as how far to fill it, if you have one of those pretty glass ones, with no check strip, then its totally upto you really, just make sure its not going to leak out of you knock it or something when its in the tank. If its a square one, like the Red Sea type, then fill it so when you turn it upright, the level of the fluid is about upto the top of the white reference strip.

Patrice ...

I am glad to see that you are active here as a subscriber <GRIN> ... I keep sending you replies to your email inquiries about your subscription that you renewed here at the Barr Report ...

Can you please reply to one of the emails so that I know that you are receiving them?

Thank you,
Greg Watson

thx Greg, I see you have look for me even on forums thx for your help

going back to that checker. I have prepare the kh4 solution. I have test it and my kh test did not showed me a kh4 (actualy, colour never changed). so I did a kh test on some distiled water. same problem. so I have trash that bad test kit.
Same thing for my ph test. before to use it in the ph drop check, I have test it with a know solution ph 7.01. the test showed me a ph of 6. I have trashed that bad test kit to.
We allways read to make sure our test kit are good. I have read this recommandation for month without doing it. I have paid for beacause I have test my water with those bad test for a while. So folks, help yourself and follow those good advise about test kit. If your lover is an aquarist to, what a gread valentine present it would be to check his/here test kit

so now I assume my solution is good beacause I followed the recipe well. I have a beter ph reagent (the one that came with the ph drop checker).

I have install it in the tank 30 min ago. colour is dark blue for now and I"me waiting.... and waiting again.

Makig the refernce KH solution to be accurate is not easy. I am hoping that Greg will sell the solution.

We should all be hoping that Greg will read this particular forum! Whomever that administrator who responded above is should contact the real Greg as soon as possible!

Europe needs an English Greg!! We might have to campaign for one.

I had a thought! (yes it happen)
Dissolve Co2 in our tank stay stable at a certain level beacause we supply a stable flow and we lose it in the air at a stable rate so what's in the tank stay stable to. but, with those ph drop checker, CO2 that gets inside can't get out so Co2 level in the kh ref solution should get higher and higher with time and one day, we'll have way more Co2 in the ph drop check that we have in our water. is this correct?