# DIY: 4dkh standard solution for drop checker



## Nicklfire

Originally posted by imisky

hey guys so there seems to be a few people asking around how to make KH standards for your drop checkers. i copied this information down sometime ago and forgot which site it was from...however this will be useful for those who are looking to make some kh standard solutions. again i didnt come up with this but i have used it and it does work, hope this helps enjoy guys.

1. Measure 3000 ml of distilled water using the 500 ml graduated cylinder and put it in a clean container. The container could be an empty 1 gallon distilled water bottle. (I found it easier to use 3000 ml, instead of the often suggested 5000 ml because you can make your standard with 1 gallon of distilled water instead of having to have a larger container or multiple containers)

To read the precise water level in the graduated cylinder.

-Place the cylinder on a flat surface.
-Make sure your eye is on a level plane with the of the meniscus. 
-The meniscus is the half-moon curve formed at the surface of liquid.
-Water should be read from the bottom of the meniscus

2. Weigh 3.60 grams of baking soda, add it to the 3000 ml of distilled water and mix well, this will make a 40 dKH / KH standard.

3. Pour 450 ml of distilled water into the 500 ml graduated cylinder.

4. Pour 50 ml of the 40 dKH standard into the 50 ml graduated cylinder 

5. Pour the 50 ml of 40 dKH standard into the 500 ml graduated cylinder and mix well, this will give you 500 ml of a 4 dKH standard.

6. If you want a 5 dKH standard instead of a 4 dKH - change step 3 from 450 ml to 400 ml and you will end up with 450 ml of a 5 dKH standard.


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