Change in Rapid Fixer Dilution?

[jmain]

The dilution for Rapid Fixer in the newer, tall 500ml bottles says 1:3 for film and I believe the older bottles said 1:4.

I did a quick bit of searching here and on your website and I can't find any mention of a change. Is this a new recommendation or an actual change in the strength of the concentrated liquid fixer?

Thanks