I would expect longer than it takes your peelers to come on.
Just a though for you. When I used to match fish I had a regular "peeler farm" going. Basically any crab with the slightest showing of a leg I could bring on. I used plastic stacker boxes at room temperature with about an inch of sea water in. You must check every crab every day. You would soon run out of legs so it is best to check for some give in the shell on the small plates of shell just above the joint for the pincer. When it "gives" time to move then to a lower temperature ± 6°C. This will slow down the rate of change. I kept these in damp seaweed in the fridge (in plastic boxes), not sea water or they will still "pop" . A couple of days before a match they go into cold sea water in the fridge (top) ,checking twice a day now. Those that start to "pop" come out of the water into seaweed again at the bottom of the fridge.
Well the fresh sea water was becoming a problem (work kept getting in my way) so I rigged up a small fish tank with an under gravel filter. This cleaned really mucky water to sparkly clean in a couple of days.
A long winded answer but the fish tank cleaning system for the water saved me loads of time going to the coast for fresh water.