I have recently thought about moving up from a 20 gal to a 40 breeder. Currently the 20 has mushrooms, a polyp coral(duno the name) and a colt, live rock and sand.Its running on a CPR and a 201 power head and a aqua clear that I use for weekly carbon.I have a rubber maid 30 gal tub and a rio 200.My plan was to have 18 gal of freshly mixed salt water in the 40 take the corals out with the water and place them in the tub with a power head for circ.I would then take the rock and sand from the 20 and place it in the 40.Once all has cleared and the pH and temp sal. were identical to what I had in the 20gal. I would then place the live stock in the tank as well. Now the question is I once heard that it was not a good idea to transfer sand when doing this type of task. The sand that's in there now is the live type which is sold in an air tight bag in pet stores (I forget the name of the company) and has been up as long as the tank 1 yr. any thoughts??