I've had issues and ended up with fairly high salinity... Just drop it very slowly
And personally, I temp acclimate the bag (float) of whatever (fish or inverts) I buy, add 50% to volume off bag of my tank water after 10 minutes of floating, let sit another 5 minutes and then net out and into the tank (I don't want other people's water in my tank) I've not had to many issues doing it this way for the last 10 years...
I've had more problems drop acclimating...