why oh why won't my nitrate go down?

[JustinMUSM]

I can't seem to get my nitrate to go down. I suction 50% of the water each week, removing most of the crud from the gravel. I'm running two aquaclear 110 filters with 300 mg of Purigen in each. It's a 150 gallon tank, so filtration should be more than enough. Nitrite and ammonia are both zero, and I haven't had any losses, but I hate to see the nitrate so high (30-60). Nitrate in my tap water isn't very high, so I don't think that is the problem. I have never replaced the ceramic rings in the filters, but I have replaced the foam blocks. Could the rings be the problem? Any suggestions (besides do more water changes) are greatly appreciated!


Justin

[Stang69]

How long has the tank been up and running?

If it has been up some time I would possiably pull da rings and rince them with room temp water. Possiably a build up of nasty ucky stuff on them.

Jeff

[JustinMUSM]

It's been running since August of last year. Anyone else have any tips? I'll replace those rings this weekend.

[Gilraen Took]

At least once a month when I do a water change I take out all of the filter media and give it a good rinse in the water I took out of the tank.