Hello. I have a 125g freshwater aquarium with a 55g sump and a 75 saltwater aquarium with a 55g sump. I have a 7" red oscar, some firemouth cichlids and gaint danios in the 125. The oscar is becoming very aggressive to his tank mates so I'm wanting to swap him into the 75g and make the 125 my reef tank. I have other tanks that the other tankmates can go. Also have a spare 75g and a 20g that I can set up temporarily to move the fish to in-between moves. Im thinking moving the oscar to the temp 75 and the other fish to their different homes. Clean the 125 and get it ready. Then start to move the marine into the 125. Clean the 75 then put the oscar in it. The 75 has alot of calcuim and coraline algea buildup as well as a good bit of pineapple sponge in the sump. Thinking about filling it with tap water and use about 13gal of white vinegar and let it run for 1-2 days to loosen everything up. I have more live sand and rocks. Does that sound like it would work? Any better ideas. Planning the swap for 2 weeks from now.