Fishman61, how much sand have you decided to go with? You probable should start with 50-75 lbs, see if that is enough coverage for you and add more if it's not.
i recently changed my gravel to sand in my 90 gallon and had no problems the only thing was the water was real dirty so I had to wait a while so that it could clear up I took out most of my fish while doing it including my discus and put them back in after the water cleared up. and I used a 50 lb bag of play sand washed it like 25 times.
I plan to start with 100lbs, I am emptying out the tank completely to we can install a new floor. I am transferring the fish into the 55, and the fish in the 55 will go into a 30 and the fish in the 30 will go into my 15 hospital tank. I plan to fill the 55 with some of the water from the 150 so the fish won't be shocked too much. Hopefully the 150 will be set back up within 3 days.
