how big is your system? 2-3 cups is a ton. You add a bunch of kalk to the reactor, and then watch it dissolve over time. You can't add "too much" per say, bc only so much will dissolve in the water that is in the reactor at any given time.
Hopefully your system is huge, bc 2-3 cups of kalk water will shoot your pH through the roof.
Please add some more info and I'll check back.
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Adellina