Noob drop checker question

mnsnowdaboy said:

Got it.....

now how much drop of chemical do you put in the drop checker, does it matter.

when do you do a refill, I assume it wont last forever does it?

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If you have a digital gram scale, that weighs 1 to 10 grams, or even 1 to 100 grams, with an accuracy of +/-0.01 grams, and an accurate way to measure quantities of water from about 10 ml to one liter, you can make the 4 dKH reference water, by adding the exact right amount of sodium bicarbonate to distilled or DI water. You start by adding 4.99 grams of sodium bicarbonate, either from a freshly opened box, or after baking it at 200 F for a half hour or so to drive out the water, to 1 liter of distilled or DI water. That gives you 200 dKH water. Now take 10 ml of that and add it to 90 ml of distilled or DI water to get 20 dKH water. Now take 20 ml of that and add it to 80 ml of distilled or DI water to get 4dKH water, which is what you are looking for. If you have a KH test kit, test a sample to verify that it is 4 dKH. (The test kit may be wrong, so don't trust it in preference to the water you made.)

Add enough pH reagent to a couple of ml of that 4dKH water to get a strong blue color, but not totally opaque. That is what goes into the drop checker. And that will last at least a couple of weeks, and probably longer in the tank before you should clean the drop checker and replace the water in it. This will give you a green color at 30 ppm of CO2, and if you can tell the difference between just slightly yellowish green and green and just slightly bluish green and green, your accuracy is such that you know you have from 25 to 40 ppm of CO2 in the tank when you see the green color. There is no other way to equal that accuracy.

Just to echo the sentiments that have already been expressed, you can easily use more drops of the pH reagent (bromothymol blue) with no adverse effects. I usually add 6-8 drops, depending on the volume of 4 dkH reference solution inside the drop checker.

Be sure to use a 4 dkH reference solution, as mentioned. Do not use tap water or aquarium water.

Chasintrades said:

Once you set up the drop checker accurately, how long do you leave it in the tank before its reliable?

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It takes about 2 hours for the drop checker to fully equilibriate, in my experience.

Chasintrades said:

I know that it can take 1-2 hour for a good first reading. But my question is after that first reading... do you just leave it in the tank for a few weeks or months?

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You are supposed to leave the drop checker in your tank at all times. It is a tool that allows for an "at-a-glance" check for CO2 levels inside your tank. The CO2 drop checker can change colours depending on the CO2 levels, so it is not a "one-shot" type test. To try it, when your drop checker turns green, take it out of your aquarium, and within a few hours, the solution should change back to its original blue colouration.

Chasintrades said:

The drop checker usually How long does it actually work? One test, or weeks or months of tests?

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Some people like to replace the 4 dkH reference solution every time they change their water. I don't see the necessity, so I just change it whenever I feel like it, or whenever the colour begins to fade. I have gone for a month without changing the solution with no noticeable negative effects.