Hypo Check formula

Does anyone have a formula for hypo check or something similar? How accurate is it for determining the exhaustion of fixers?
Denise Libby

I have no idea about the formula but in the age-old "answering something you did not ask" tradition I would mention that you can easily check the freshness of fixer with a piece of undeveloped film. A new fixer should clear a film in about 30 seconds. If you get substantially longer times, toss it.

r

Mats

The product is a potassium iodide solution ("potide") of less than 5% concentration according to the MSDS.

From digitaltruth.com:

Fix Test (Hypo Check)
. . . . . . . . . . . . . . . . small batch . . . . . .10x batch
Potassium Iodide . . . . . 5 g . . . . . . . . . . . 50 g
Water . . . . . . . . . . . . 100 ml . . . . . . . . . 1 L

On that page it also says,"This solution should work well for modern rapid fixers based on Ammonium Thiosulphate, but for fix formulae based on Sodium Thiosulphate you may need to double the amount of Potassium Iodide."

www.digitaltruth.com/techdata/fixtest.php