i disagree with salty's method, especially if the inverts have been shipped.
"while no one else probably does this, I float all inverts for 24h before adding any water. Then I slowly add tank water over a 12 hour period until the SG is the same in both the tank and bag.
I know it is overkill, but I have never lost a critter using this method."
why place them in deteriorated water longer than they should be? when snails are shipped, they are shipped in very little water as this increases their survival rates and they do not end up drowning themsevles in the water they fouled. i do agree that inverts need to be acclimated, but the 24 hour floating part seems very pointless to me, as the temp should equalize much sooner than that.