-Floating Method:
Float the sealed bag in the aquarium for approximately 15 minutes. The reason for this is that sometimes the temperatures between the aquarium and the water in the bag are very different. Opening the shipping bag prior to letting the temperature equalize may lower the level of dissolved oxygen quickly and additionally stress your new arrival.
After 15 minutes of floating, cut the shipping bag open under the metal or rubber band clip. Roll the bag down about three or four folds (like rolling up a pant leg). This will hold air and enable the bag to float on the water surface. It is also recommended to use a clothes pin or hair clip to hold the bag in place on the side of the aquarium. This will be helpful if you have a lot of current in your system that may push the shipping bags around and even knock them over. If you are acclimating a coral that is large or heavy, place the bag in a plastic bowl or bucket.
Every five minutes pour a half a cup of water into the floating bag. A turkey baster (which you can purchase at any 99 cent store) will be perfect for this as well. Repeat this step until the shipping bag is full.
Remove the shipping bag from the aquarium and carefully pour out half the water from the bag. Take care to not accidentally pour out your fish or coral. Pour the old water into a bucket which you can dump out later.
Re-float the shipping bag again in the aquarium and continue to add ½ cups of aquarium water every five minutes until the bag is full.
If you have a fish that is safe to net, you may net it out of the bag and release into the aquarium. Net handling can easily damage some tangs, angels, sharks, and others. When at all possible try to pour off as much of the acclimation water as possible, and transfer the animal to a collection cup or bowl.
Remove and discard the acclimation bag. Try not to let any more acclimation water into your aquarium than you absolutely have to. Sometimes, to ensure the health of the fish during shipping, or even at our facility there may be medication in the water that can be harmful to inverts and other fish.
for inverts i usually repeat the pour and re-fill the bag again for a third time