Hi, I need some help. I have a 48 gallon tank. I have two Shubunkin Gold Fish in my tank and that is it. I'm having a real problem with Nitrates. Everything else is within normal limits except them. I clean my tank very throughly every other week, replace about 15+ gallons of water, wash everything really well, rinse the filter media in the fish water instead of clean water every time I clean my tank but I can't get the Nitrates down. My husband has forbidden me to get a larger tank just for two gold fish. He's not a bad guy, it's just we have space problems and have no place to put a larger tank. OH Did I mention that my boys are about 8 inches long without the tail and about 2 1/2 inches thick??? I've had my fish for three years, my bigger tank for 2. I have two air pumps to pump air into the tank and the filter I have is the Aqua Clear 100. I follow all the directions with my water, let it sit out for 24 hours before I use it etc etc, I use Cycle when I do my water changes. Does anyone have any ideas what I can try next? They still have pink gills which is amazing since they have these high nitrate levels. I want to keep them healthy but I've run out of ideas.