Guys I need some input here. I have a 55gal tank with 20gal sump that is full of LR and expensive corals. I bought a Reefer XXL750 and getting ready to swap them out. Have any suggestions what the best way would be to do this? If I use my old tank water for new tank and then add all new water that would be like a 120% water change! You think maybe I should do an aggressive water change first in my old tank say 30 or 40 gal and save that water to add in the new tank? That way it would almost be like 100 Gal of old water I'm putting in new tank? Thoughts? Thanks !!!