If nitrates are high, a few water changes might help before dumping the tank. How long has the tank been set up and what type of filtration are you using, what are you phosphate levels? Although I'm a fan of truely live rock, it still won't cure all problems. I'd get the chemistry right, figure out what the exact problem is and look for alternative solutions without dumping the entire tank and starting over or you might find yourself in the same position in the future.