Your tank is 75-gal, 48"x 18"x20"? That tank is 600 gal, 96"x48"x30", 1" thick acrylic, 10+ years old, with a light hangs 2-ft above the tank. It's not the water clarity. It's the lighting issue. Plus clear water doesn't mean good quality.i can see through 4' of water in my tank like it doesn't even exist. i can only imagine how those fish feel in there, I can't imagine that water is of good quality.