W/C's and drop in SG

[bv_reefer]

-just wondering what do you guys do when you have to do a big water change and you're SG drops, do you're fish and inverts such as corals,anemones, and crustaceans get really stressed with the decent drop in SG? -i just found a snail thats been dead in the same corner for a week and it gave out the most putrid smell i've ever encountered, and i'm guessing it could also be part of my cyano-outbreak thats plagueing my sand..