First post here as the forum was recommended by a friend. I have a 70g reef tank that needs to be 'upgraded'. Just installed an RO/DI 5 stage system, and need to relocate sump, to make room for a Refugium. Sump is going downstairs (about 5' below tank, and about 15' of linear pipe away). want to pipe all RO/DI Saltwater from holding tank (also newly installed)into sump, and drain from sump to slop sink, a few feet away from new sump home. My question is, should I go with 3/4" pvc/pex combo, or 1". Currently,the sump housed below the tank, uses a RIO 2500, with what appears to be 3/4" soft tubing back to tank. I know its not a ton of info, but any suggestions will be greatly appreciated. I am also aware that the Rio 2500 will likely be needed to be upgraded.