To make a long story short, I was over feeding the fish in my tank and that had the numbers high. I have since corrected this over feeding problem and as of say three weeks ago and the numbers I thought would be starting to go down and they aren't. Yes, I have been doing weekly water changes in the tank of about 27g a week in a 125g tank. The one thing I might be doing that is keeping my numbers high is I put two leaves of Romain lettuce in the tank each day before going to work to give the fish something to munch on during the day, I give them a piece of Nori in the evening (small). So, my question, is this Romain lettuce keeping my nitrate numbers high?