Fixing my high Nitrate tank issue.

I have high Nitrates in my tank. This happened because I wasn't watching what I was doing. I finished my cycle, changed 50% of the water but didn't test after I did the water change. Sunday night I had somewhere in the 160 range. I did a 15 gallon water change (75 gallon tank) and retested to about 80. I did another 15 gallon water change Monday night and I'm somewhere between 40 and 80 but it seems closer to 80. Maybe I'm color blind but the difference in colors on the chart between 20 and 80 is minimal. I'm using the API Master Freshwater testing kit.

Anyhow, I wanted to know if doing 15 gallon water changes every night will be too much? Should I wait a day or two between changes?

I currently have 15 fish in the tank; all between 1 and 2 inches.

Thanks.

Thanks. I'll step up the amount that I'm changing. I deserve what I'm getting. You know, you can be carefull about almost everything. One small slip-up and blam-o.

I also, I took the opportunity to remove the carbon filter from the Eheim 2215. The manual said to keep it in there for the first two weeks and then remove. When I removed I somehow loosened the hose on the intake and caused a leak. I'll get this all straight one day.