Need to Raise Calcium


New member
Due to factors beyond my control, I was unable to test the Calcium levels in my tank for the past little while. I had thought that larger waterchanges in the meantime could keep my calcium up until I was able to test again. When I tested today, the calcium was 150 mg/L. What's the best way to raise this back to where it should be, and how slowly should I do it? What is the best method? I currently only have Kalkwasser, so I'll have to buy something else anyways, so that part doesn't really matter. Thank you.


New member
I use the calcium portion from the recipe of Randy's two part which in my case consists of prestone driveway heat. Mix according to the directions (see following) and then dose according to caculator.

Excerpt>>>>>Recipe #2, Part 1: The Calcium Part

Dissolve 250 grams (about 1 ¼ cups) of calcium chloride dihydrate (such as Dowflake 77-80% calcium chloride or ESV calcium chloride; see below for substitutes and sources) in enough water to make 1 gallon of total volume. You can dissolve it in about ½ gallon of water, and then pour that into the 1 gallon container and fill it to the top with more freshwater. This solution is about 18,500 ppm in calcium.

If using an anhydrous or monohydrate calcium chloride (such as Dow Mini-Pellets, Kent's Turbo Calcium, Prestone Driveway Heat or Peladow Calcium Chloride), then about 20% (1/5) less solid calcium chloride by volume should be used to make the recipe. Note that the solution will get quite hot when dissolving anhydrous calcium chloride. See the section on substitutions for further information.>>>>>>



Premium Member
Calcium chloride, such as Dow Flake or Turbo Calcium, should be fine. I'd raise it no more than 100 ppm per day.