Do you think this will cause a ph swing?

[fronty]

Fluval edge 12 gallon

It doesn't get much evaporation, since the surface area is small. I do not have an ATO. I was thinking about making a jug of kalkwasser and just topping off the tank daily. Do you think this will cause too large of a PH swing?

[disc1]

Define, "Doesn't get much evaporation"

Dumping kalk water in all at once is almost never a good idea, but if the amount is small you could make it up and set up a drip line or something to deliver it to the tank slowly.

[fronty]

I would say maybe a cup or two a day. Maybe less than a cup. I would need to measure.

[bertoni]

If the Kalkwasser is dripped slowly enough, the pH will be fine. You'll need to experiment to find a good rate. Adding that much Kalkwasser in one shot likely will raise the pH too much.