potassium calcutaion related to calcium

[redadeath]

i found this thread
can any body verify it please

Potassium Chloride Calculator
I have been dosing Get Tanked's Potassium Chloride for the past few months and wanted to share how to calculate the amount of potassium to be added to our reef tanks. Potassium chloride is 52.5% by weight potassium. With this calculator, use the calcium to find your potassium. Desired potassium should be between 390 and 400 mg/L. Select Anhydrous CaCl2 (Dow's Peladow) and enter your current and desired potassium values. When entering in your systems water volume make sure to include the live rock and sand displacement (8.556 pounds of rock/sand displaces one gallon of saltwater). After you find how much "calcium" to add, multiply this result by 0.7 to find how much calcium needs to be added.

original thread
http://rickysreef.blogspot.com/search/label/Potassium%20Chloride

[bertoni]

The 52.5% is about right. The percentage is about 36% for calcium per unit of anhydrous calcium chloride. What is the purity of the KCl supplement? I'll need to locate the purity of the Prestone product, too.

[Randy Holmes-Farley]

Redadeth, have you found you needed much potassium? Many folks (myself included) have not found a need to supplement potassium. :)

The calculator procedure is probably very roughly useful (assuming one uses pure potassium chloride). The result by volume is less accurate than the weight based result as the volumes are for calcium chloride solids not potassium chloride solids.


When entering in your systems water volume make sure to include the live rock and sand displacement (8.556 pounds of rock/sand displaces one gallon of saltwater).

There's no reason to think that is accurate. It is obviously way too precise, but I'm worried it may not even be close to accurate. I've never seen any actual data on the density of live rock. It is not as easy to do as it sounds as some air or water spaces in the rock may remain out of contact with the bulk water, and some only very slowly in contact with it.