A dying question?

[shimmy]

ok my tank is a 72 gallon and been setup for about 2-3 months (I think maybe less)
ok for the water change I remove 2 pails (3 gallons a pail i think) of water and then add 3 buckets over the course of several hours. I always remove the water first the add fresh. I float the new buckets of water in my tank to get them up to proper temp to insure I do not send a cold or hot wave through my tank (reason it takes several hours to do a change) I perform a water change every couple days for I dont have enough time in the day to do the 25%. I always match the salt close to the tank or slightly lower depending on the current salt of the tank.

break down
remove water
fill bucket with fresh
add salt
add chemicals as needed (i.e. Prime)
mix and check again
float in tank to get to even temp
dump bucket slowly into tank.

Water change was done early in the morning finished around noonish

my tank is filtered using a Fluval 304.
I use a 300W heater to maintain temperature(never turns on for between my condo and the lights its hot... 83 F)
I use a powerhead I cant recall the maker but its a 1600L/hr

nothing new has been added to my tank since sunday.

only my hermit crabs are still alive but dont look good
all my corals look good

any other questions?