Things are going good on the big tank - made some progress this weekend. The back of the tank is painted navy blue (looks a bit lighter in the tank, but cool) and the sand is washed. I put the sand in the tank and filled it half way and let it sit overnight. It was a bit hazy last night, but is a lot more clear this morning. How long before I should start my filter up - I don't want to mess up my filter. The filters are HOB Aquaclears. I bought one new filter and will be taking an existing filter off my smaller tank to get my large tank going.