Hmm... Thanks for the answers, everyone. My current alternative would be a tank of lake Malawi cichlids in a 75. I'm not worried about hard water; the water where I live tends to be very soft but extremely high in pH, as much as 9.2 at times. How that's considered drinkable is beyond me. The last tank I had I actually added stuff to bring the hardness up and stabilize the pH to where I wanted it. I probably won't do an oscar tank after all, but maybe some day!