Frio wallets info needed

So im going on holiday and never used frio before. I have a duo pack which need 8 mins for the Crystal's to absorb the water. After 45 hours when they suggest to put it back in water do I do it for another 8 minutes or 2-4 mins which it says for continuous use. I thought that 8 mins might be too long as it wont be in crystal form.