I know there are a lot of fans of this method out there and I would love to hear why those people stick with this practice
Okey, here's what I've done. I, too, have a Tunze osmolator, then decided to do kalkwasser just like you.
My tank evaporates about 20 gallons a week, so I used a 22 gallon bin as a reservoir. I cut up a plastic eggcrate to use as a plaform for the pump, then put 2 tsp/gallon kalkwasser, and let the thing run.
Worked well.
BUT.......I didn't like it. There's always a milky residue on the bottom, and a crusty surface film of calcium carbonate as well. Looked messy. Plus, the tunze tubings are so small I was always worried about the thing clogging.
So, I bought a Kalkwasser reactor. For the price and genius simplicity, you can't beat the TLF kalk reactor. he only issue was making the connection between the small tunze tubes and the larger reactor tubes. I just used progressively larger tubes 1" in length and nested them like nesting chairs, and it worked as a bridge between the two.
Here's the 22 gallon ATO reservoir. Clean as a whistle, since there is no kalkwasser.
Here is the TLF reactor, I hung it close to the drain for my remote refugium. The Tunze pump fires for a few seconds, delivering just enough so that only the clear kalk saturated water gets delivered. Between deliveries, the stirred up undissolved kalk powder settles back down, leaving a clear kalk saturated supernatant for the next delivery.