Equal calcium and alkalinity dosing

[ReefDreamz]

Main question:
Is balanced Ca and alk dosing 8.45 ppm Ca for every 1 dkh?

More details:
I made a solution of 50g/L Brightwell Alkalin8.3P and a solution of 100g/L Brightwell CalcionP.

According to the instructions:
Each g of Alkalin8.3-P will increase the alkalinity in 1 US-gallon (3.785 L) of water by 12 dKH.
Each g of Calcion-P will increase the [Ca2+] in 1 US-gallon (3.785 L) of water by 95 ppm.

So let's say I want to dose 0.15 dkh of Alkalin8.3P per day for a 200 gallon system. According to their formula (volume x desired dkh raise x 0.089) that's 2.67 grams per day (53.5 ml of my 50g/L soln.).
If I also dose 2.67 grams per day Calcion (26.7 ml of my 100g/L soln.) that's 1.26 ppm calcium.

Thats a ratio of 8.45 ppm Ca for every 1 dkh if you dose an equal weight of powder. Is that the proper ratio?

 

[Jekyl]

Ummm...

@Randy Holmes-Farley

 

[nereefpat]

Main question:
Is balanced Ca and alk dosing 8.45 ppm Ca for every 1 dkh?

It's closer to 7 ppm Ca: 1 dKH

The goal isn't to dose an equal weight of powder, but to replace alk and Ca at close to that 7:1 ratio. (I believe it's actually something like 19 Ca: 2.8 dKH

 

[Tavero]

From Wikipedia:
"1 dKH is defined as 17.86 milligrams (mg) of calcium carbonate per litre of water"

Calcium Carbonate contains 40% Ca2+.

17.86*0.4= 7.14 ppm

 

[Randy Holmes-Farley Verified Community Expert]

It’s a little complicated in a reef tank because it depends on how much magnesium and strontium get into the calcium carbonate in place of some of the calcium.

Perfect calcium carbonate is 20 ppm calcium per 2.8 dKH, or the 7.14 ppm per dKH that folks mention.

But it is more typically 18-20 ppm per 2.8 dKH in a reef tank, so can be as low as 6.4 ppm per dKH.