How to lower Nitrates?

[Money pit]

When I had a 30g skimmer less lps/softy tank, I used to do 50% water changes a week. There was always some NO3 from feeding the lps, but usually only around 5ppm at water change time. It was vital to match temp and ph, if this was done there wasn't any problem caused by the large water change. May not be a long term solution, but it will cut down the NO3 fast, while you look for the cause.