Here's a thought or suggestion. When the snails arrive take them out of their bag and put the water and snails in a five gallon bucket. Then put an old airline hose in your tank with a small shutoff valve on it. Use the kind we all had on our freshwater tanks that controlled the bubble maker (remember that  ) Start siphoning water out of the tank into the five gallon bucket and adjust the valve so that it slowly drips in. After doubling the volume of water and letting them sit in there for about an hour and a half. Pick them up and put them in the tank.
If I buy mine locally, I ususally just float them for a half an hour and them place them in the tank. If I get them shipped in, then I use the method I just described.
Jim
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90 Gallon glass, 135#'s of rock and 2" sand. 2-250w 20k XM metal halides. 2-95 watt actinic VHO, 4 powerheads, Coralife skimmer. Maroon Gold Striped Clown, Blue Chromis, Kole Tang, Pygmy Angel, Serpent Star, Brittle Star,Gorgonians, Mushrooms, Yellow Polyps, Turbo Snails & Blue Legged Hermits. 20 gal sump with Caulerpa, Mag 7 return pump. | 
Problem with Snails 
