Too much nitrate!

[busdriver]

Just did a large water change on my 150 yesterday, at least 50% and I still have too much nitrate.
Test results were:
Ph - 6
Ammonia - 0
Nirite - 0
Nitrate - 20 to 40 ppm
Any suggestions?

[kennyman]

Do you have any plants in that tank?  Something simple and vigorous might help to suck up allot of N.

[dan2x38]

'busdriver'- prunning out some water sprite great NO3 sponge can have some if you want... grows fast can float it so does great gas exchange too...

[BigDaddy]

20 to 40ppm isn't really high.  Give it a day or two, and do another big waterchange.  You don't want to be doing large waterchanges like that back to back.