Thanks for the link.
All I can say, is WOW. That detailed analysis of the ions present:
http://www.drsfostersmith.com/product/add_info.cfm?pCatId=12804
Guaranteed Analysis
Calcium (Min) 1650.0 mg/oz
Magnesium (Min) 75.0 mg/oz
Strontium (Min) 5.8 mg/oz
Potassium (Min) 2-1/2 mg/oz
Iron (Min) 0.124 mg/oz
makes me wonder how good (or bad) the commercial two part systems are, despite claiming to be balanced. And here the values are touted as if they are suitable.
I would not use that product for these reasons:
It seems quite low in magnesium to me. Only 22% of what I add in my DIY two part recipe, relative to the calcium provided.
The potassium seems way, way too low to be balanced. Mine has potassium as 3.6% by weight of the calcium, and in my analysis, that is actually a bit too little. This product has it as 0.15%.
Here's my DIY recipe and the residual ion calculaton:
An Improved Do-it-Yourself Two-Part Calcium and Alkalinity Supplement System
http://reefkeeping.com/issues/2006-02/rhf/index.php
and the analysis of the ions in the calcium (Dowflake) that is used:
http://www.advancedaquarist.com/issues/mar2004/chem.htm