ADA drop checker

[dagger13]

hi i just bought the ADA drop checker but the thing is the moment i drop my aquarium water into the drop checker after putting a drop of the reagent the soulution turn yellow and this is when there is no Co2. even when the Co2 if off its still yellow which indicates too much Co2. is the soulution turning yellow because of my ph is at 6.2 or must i actually put normal tap water which is neutral so that the colour would be at blue and then place the drop checker in the tank so when the Co2 is turned on then the colour would change to green. please enlighten me on this to those who are using this. thank you

[gemo82]

The reagent turned yellow because your tank water is at pH 6.2. The reagent is only a pH indicator, changing colour corresponding to pH.

To indicate the amount of CO2 there are in your tank, you need a reference solution with a known KH. Usually, a 4dKH solution is used so that when the reagent turned to green, it indicates around a pH of 6.8 that is due to the CO2 and none of the other factors that affect pH in your tank water. As such, your CO2 level will be around 30ppm, according to the KH-PH chart.

You can read more about this and learn to make the reference solution from the following links:

http://www.barrreport.com/articles/2...s-why-how.html
http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm

[dagger13]

hi thank you for responding to this thread but the link to make the reference solution is not working.anyways can i just use my tap water for this?

[Shadow]

No you can't use tap water, tap water kH on singapore is about 0. You can make your self kH=4 solution using baking soda or if you stay near my place (telok blangah) I can give you some. I made about 1 liter some time ago

[jacian]

You may want to read this http://www.aquaticquotient.com/forum...ad.php?t=35944

[gemo82]

Our tap water has very low, almost zero KH, as mentioned by some bros in this forum, thus making it not suitable. Anyway, you need to target the amount of CO2 you want, then use a solution which has a KH that corresponds to the colour change of your pH indicator.

To simplify it, if you want 30ppm (as normally recommended), you will need to use a 4dKH solution so that when your indicator shows green (around pH6.6), you have roughly 30ppm of CO2 in your tank. For 23ppm, you need to use 3dKH, so on and so forth....So you really need to get a solution of a targeted KH level to use the drop checker.

To make the reference KH solution, you need to use distilled water and add a little sodium bicarbonate (baking soda). You can either do some chemical calculations and use lab equipment to mix it, or mix something at home and test with a KH test kit and keep diluting till you get what you want.

Hope I explained correctly and that you know what to do now. Do search this forum for KH solution, or drop checker, or CO2 indicator to learn more. Also, goggle on CO2/ KH/ pH table or calculator.

Hope this helps.

[dagger13]

no worries i know exactly what you mean gona try it out today its just that i want to make sure im using the drop checker correctly as ADA instrution regarding the solution is very misleading. trhank you so much for the infos regarding this.

[Shadow]

yes it does very missleading, I had the same problem before.

[dagger13]

as im using ADA soil which my ph is 6.2 therefore in accordance to the Co2 table should i make my kh solution to be at 1dKH so that i have ok Co2 level?

[gemo82]

No. 6.2 is the pH of your tank water. Like you said, ADA soil has lowered your tank water's pH, therefore knowing the tank water's pH will not help in knowing your CO2 concentration.

What we are trying to achieve here is to have a known KH value of the water in your drop checker. As the pH in the drop checker is only due to CO2 (unlike that which is in your tank water), we can use the chart to check the concentration of CO2 in the drop checker, which is also the concentration of CO2 in your tank.

Since your indicator solution changes colour in the range of pH6.0-7.2, you want to use a KH solution that gives you the required CO2 when the pH is in that range. Look at the pH column under that range, find the CO2 concentration you want, then see which row you are at with the KH.

[dagger13]

what you are saying that i know.guess you must have misread what im trying to say. what i was saying is that since my ph is 6.2 therefore shud i make solution to be at 1dKH in accordance to the Co2 chart and add it to the reagent of the drop checker.

[gemo82]

No no. You do not use your tank's pH value as we are reading the pH of the reference solution in the drop checker, not your tank water. Starting at a neutral pH, the reference solution with a pre-set KH in your drop checker will remain pH 7.0 till and only due to CO2 injection.

So you do not read your tank's pH at all for knowing CO2 concentration, unless you are sure there is nothing else that alters your tank water's pH other than CO2 (which is almost impossible: ADA soil, driftwood, peat, urea from fauna etc.)

Simply say, just ignore pH, use a 4dKH solution and when you see green on your drop checker, you know you have roughly 30ppm of CO2.

[dagger13]

ok got it simply to say ill just have make a 4dKH solution.

[route]

correct. you should see the change in colour of the dkh 4 "solution" turn from blue to green.

[dagger13]

so who have 4dKH solution to spare?