Photographers' Formulary Sodium Metaborate, octahydrate (8H2O), and Balanced Alkali (Kodalk) are, for all practical purposes, the same. Substitution can be made weight for weight.
A substitution for sodium metaborate octahydrate is to use 9.5 grams of sodium hydroxide and 45.4 grams of borax decahydrated in water to make 1 liter. This is equivalent to a 10% solution of sodium metaborate octahydrate. This can be made from Red Devil Lye and 20 Mule Team Borax and safely used in formulas as a substitute (20ml of a 10% solution = 2 grams; 25ml = 2.5 grams; etc.).
Photographers' Formulary 10-1285 10G Specs
Kodak balanced alkali Kodalk
White crystals An ammonia-like odor
As a mild alkali accelerator in developers of moderate to high alkalinity. Used to avoid the creation of gas when it comes in contact with an acid. For this reason the possibility of blister formation is minimized.
Kodalk or "Kodak balanced alkali" is Eastman Kodak Company's trade name for sodium metaborate. The largest supplier and research institution for this compound is U.S. Borax Research Corp. in Anaheim, California.