Before anyone nukes their tanks:
Dosing procedure
Use 1 teaspoon per gallon of RO/DI water. Mix it well.
Let it settle for an hour, or even overnight.
Siphon out all the kalkwasser into your dosing container, making sure not to suck up the sediment nor the skin on the surface - these are not to be added to your tank.
Set up your drip rate in an area of high flow, from 1 - 3 drops per second.
Keep in mind, there are other ways and each person's system is different. You'll need to tailor this to the needs of your tank. (.5 to 2 tsp per gallon)
Kalkwasser has a pH of 12. You need to be careful that you don't overdose the tank.
Kalkwasser can cause some pumps to seize up as the impellar becomes coated with deposits. The pumps can be cleaned by soaking the impellar in vinegar and water.
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Some use kalkwasser as their top off source. Do your reef a favor and limit the total amount that could possibly be added in one session if everything possible went wrong. If you have a 29g tank, you don't want 10g of kalkwasser in your top off resevoir. 3g would be risky, but survivable.
Please ask for more input before you try this out, and don't assume anything. We have plenty of members that have used kalkwasser and can help you get a good understanding of what you can and can't do.