Can anybody tell me the correct length of time a fox hide should soak in the pickling solution? I have looked around a bit, and found everything from 30 minutes, to 72 hours. I am using the McKenzie ultimate acid for my solution, mixed down to 1 on the ph. I have done several coon, and a few coyotes now with no problems, but the foxes seem like they are always wanting to slip. Any help would be much appreciated. I just hate to waste this beautiful fur that took a lot of effort to catch.

Likely not the pickle causing them to slip.
The fleshing or washing-rehydrating is where I would look..

By fleshing too hard/tight to the hide?

If salinity and pH are properly maintained, hides can last in the pickle for years. Most tanning requires hides to be in the pickle 48-72 hours. Foxes are pretty thin skinned and if you dont get them skinned out immediately and its warm out, you can have issues. Most slip issues are caused before they even make it to the pickle process.

A pickle is ph 1,to 1.5.
A tan is ph 4 to 4.5.
You need to neutralize as well as remove any salts from the hide.
Salts left in the hide after tanning are hygroscopic and will draw moisture from humid air.
This is the cause of clammy leather when the air is humid.This causes the leather to break down over time.
Tanning oils with ammonia will help if the skin is slightly acidic.