# KH and drop checker

1052 Views 2 Replies 3 Participants Last post by  Left C
Just setup a new 75 g tank, 265w cf, pressurized co2 and ph controller....I'm having an issue with my drop checker readings. They seem to high (yellow)...Anyways, I want to make sure I'm reading the KH properly....I use the hagen test kit....I put one drop in the vile, shake it up , it turns blue...I then add drops until it turns yellow..In my case, it takes 5 drops (after the inital drop) to reach yellow...So does this mean my KH is 5?...I also test the Drop checker solution I made and it takes 4 drops to reach yellow..Is this right?...

When I set my PH to 6.7, the drop checker indicates a very high level of CO2..When the PH is at about 7 is seems right to the drop checker but low according to the PH/KH chart....

thanks...
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OK, I'm not familiar with the hagen test kit, but I don't think you should count after the initial drop. You should count total drops.

Also, If you want to be more accurate you can count the number of drops it takes to make 20 ml (instead of 5ml) of water change, and now each drop will represent 2.5 ppm instead of 10 ppm.
The Hagen KH test kit measures KH in ppm (mg/L) and not dKH, but you can convert it to dKH.

One drop equals 10 ppm.

Let's say that your end point occurs at 5 drops. That's 50 ppm. On the back of the directions there is a formula to use to convert ppm to dKH. You multiply 50 ppm by 0.056 to get dKH. So, 50 ppm x 0.056 = 2.8 dKH.

You can convert dKH to ppm by multiplying the dKH by 17.86. In this example, 2.8 dKH x 17.86 = 50 ppm

API's KH test kit works differently. 1 drop equals 1 dKH.

I thought your name was familar. http://www.plantgeek.net/forum/viewtopic.php?t=10346
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