I'm really confused about this subject. I have now made up 4 batches of 4 or 5 dKH distilled water, and all of them test way off with my KH test kit. Today I got disgusted with the process and bought a new test kit - same problem. I made up a 4 dKH solution, but the kit says it is less than 2 dKH.
Here is what I did:
Baked a tsp of freshly opened sodium bicarbonate at 230F for about 10 minutes. Used my 100 gram capacity scale to measure 4.99 grams of that baking soda. Added it to a one liter measuring flask. Added one liter of distilled water to it, making sure all of the soda was dissolved - none left on the sides of the flask. That should have give me a liter of 200 dKH water.
I mixed 10 ml of that water with 90 ml of distilled water, which should have given me 100 ml of 20 dKH water. Then I mixed 80 ml of that water with 20 ml of distilled water to get 100 ml of 16 dKH water.
I added 300 ml of distilled water to that to get 400 ml of 4 dKH water.
But, two different API test kits say it is less than 2 dKH water. So, what did I do wrong?
Some of us do not have much background in mixing up chemical solutions, measuring weighed amounts with known volumes of water, etc. so what seems easy to some isn't to others.
I had calibrated the scale with a 100 gram and 50 gram weight, and it was right on. I also tried it once with a very light piece of paper to hold the soda as I weighed it, and a second time with a heavier piece of plastic and reset the scale to zero to account for the tare weight.
Here is what I did:
Baked a tsp of freshly opened sodium bicarbonate at 230F for about 10 minutes. Used my 100 gram capacity scale to measure 4.99 grams of that baking soda. Added it to a one liter measuring flask. Added one liter of distilled water to it, making sure all of the soda was dissolved - none left on the sides of the flask. That should have give me a liter of 200 dKH water.
I mixed 10 ml of that water with 90 ml of distilled water, which should have given me 100 ml of 20 dKH water. Then I mixed 80 ml of that water with 20 ml of distilled water to get 100 ml of 16 dKH water.
I added 300 ml of distilled water to that to get 400 ml of 4 dKH water.
But, two different API test kits say it is less than 2 dKH water. So, what did I do wrong?
Some of us do not have much background in mixing up chemical solutions, measuring weighed amounts with known volumes of water, etc. so what seems easy to some isn't to others.
I had calibrated the scale with a 100 gram and 50 gram weight, and it was right on. I also tried it once with a very light piece of paper to hold the soda as I weighed it, and a second time with a heavier piece of plastic and reset the scale to zero to account for the tare weight.