View Full Version : Calcium magnesium strontium ratio

09/27/2017, 09:50 PM
I am reworking some of my math for my two part solutions and such. I have a couple questions I wanted to bounce out. I found somewhere that the magnesium uptake using the two common anions found are in the ratio of chloride hexahydrate to sulfate heptahydrate at 9.6:1. Anybody know if that is true or close? I don't know if that is the concentration of those anions in NSW or the use/deposition ratio.

Second question what is the calcium magnesium and strontium uptake in the average stony dominated aquaria? I see that Seachem lists it at 100:5:0.1 does anyone know if this is close?

Is there a strong recommendation on a powered complete trace element compound in the trade.

I know there are all kinds of caveats to the answers to all those questions just wondering what is out there.

09/28/2017, 03:55 PM
The uptake for calcification is just magnesium. The sulfate and chloride are left in the water. The ionic content of saltwater dictates the ratio of magnesium chloride to magnesium sulfate unless you're using the DIY two-part, which adds chloride to the water over time due to the calcium chloride in it. This article goes into supplement design:


The ratio you have is fine for tanks that are using a calcium reactor, a commercial two-part, Kalk, or are getting a reasonable rate of water changes.

09/28/2017, 08:49 PM
Thanks. I get the anions are not used in calcium deposition, I did not make that clear, but I have to add Sulfate or Chloride with the mag and I assumed possibly in error that there is some balance on how much of those ratios of anions I should add to stay as close to NSW as possible. I guess I wondered if sulfate precipitates, or if sulfate is the source of sulfur required for protein synthesis and other biochemistry of life and therefore utilized as some rate. I am contemplating addition of mag with NSW anion ratios versus some rate of use/loss of the sulfate. Of course water changes are always an answer but I like to manage the ins and outs myself and minimized the water changes.

09/28/2017, 08:52 PM
Thank you for that link I read that before but forgot where I got the 9.6:1 ratio.

09/28/2017, 10:29 PM
You're welcome! Any sulfate or chloride consumption would be minor. The only exception would be mass export of algae or the like. :)