Dosing Kalkwasser

Randy Holmes-Farley · Feb 2, 2024

lrlivingston said:
Question: I run kalkwasser in my ATO but somehow my alk got up to 14. If I switch to regular RO water for top off and dose mag and cal will my alk decline?

Yes, but I cannot see that likely being needed. For kalkwasser to have raised alk it MUST have raised calcium proportionally, and if you dose nothing, you should get back close to where you were previously.

Let's just ignore magnesium for now since testing is typically less useful than one would like (e.g., often inaccurate), but what calcium level do you have?

lrlivingston · Feb 2, 2024

450 cal
1450 mag

Randy Holmes-Farley · Feb 2, 2024

lrlivingston said:
450 cal
1450 mag

I would not dose either right now, and let alk decline while you do whatever normal water changes you do. :)

tzabor10 · Feb 2, 2024

Kalk can be tricky. I accidentally got my Ca2+ up to 700 range. Keep the Kalk out of your ATO! Your pumps can’t handle it. 2 months tops, then all gummed up. Go with a Kalk reactor like someone mentioned before. Or just save the headache and get All4 reef
I would seriously recommend many daily water changes.

Randy Holmes-Farley · Feb 3, 2024

tzabor10 said:
Kalk can be tricky. I accidentally got my Ca2+ up to 700 range. Keep the Kalk out of your ATO! Your pumps can’t handle it. 2 months tops, then all gummed up. Go with a Kalk reactor like someone mentioned before. Or just save the headache and get All4 reef
I would seriously recommend many daily water changes.

To be honest, what you are suggesting does not make chemical sense. To boost calcium by 300 ppm with kalkwasser, alkalinity would rise by 42 dKH, which obviously did not happen.

I also disagree on a kalk reactor. I dislike them for several reasons, including the fact that they are often producing less than saturated kalkwasser. They can work, of course, but I do not consider them an upgrade over a settled reservoir.

I also delivered kalkwasser by ATO for 20 years. If setting up again today, I'd probably use a dosing pump instead to better control the rate and timing of delivery. The two months and then gummed up comment was certainly not the case in my setup. lol