Well, I'm currently taking 10mg/kg, and it has shown a (possible) result, thus now I'm increasing it to 15, and in about 10 days, to 20mg/kg.

I got myself a highly accurate scale, and now simply pour a bit of water in a glass, set it on the scale, reset the scale to 0, fill it with the correct amount of DCA, fill more water into the glass, swirl it about, and simply drink all of it right there.

The powder is not in the fridge, but stored in a dark and cool place.

The dosage you mentioned sounds correct. I started with a relatively low value, and slowly (over a three weeks) increased to the current dosage.
The dosage of water... well, I fill the cup, drink it all up at once, and refill the cup twice again (with normal tap water, as before), drinking this as well. This is apparently to make sure that your stomach wall is not damaged (low danger, but better safe than sorry).
Keep in mind to use straight cold tap water, don't warm it up!

My Scale is accurate - it shows 0.00 gram (max. 200 gram) and cost me about 30 Euro on eBay. I got it together with 2x 100g weights, to confirm the accuracy.

Best of luck to you, and return greetings also from Germany

Ciao,
Klaus