water problems

[puff(er) daddy]

I had my tank up and running for six months now and at first I had high nitrites and now that the nitrites are down I have high nitrates. What's the problem I have a wet/dry filter and a small powerhead. One Mappa puffer and about 3 inches of sand.
I can't think of anything else right now that you might need to know to help me but give me any info you can.

 

[b_ball12_99]

Does your wet/dry have a carbon pad? If so then nitrates can generate in the pad and carbon and need to be rinsed out once a week or two. Did you add any ls to your tank so seed the other sand?

 

[puff(er) daddy]

Sorry b ball for the late reply, but yes I do have carbon in my wet/dry. No I didn't seed the sand yet I'm in the process.
What are some inverts that I can add to clean the sand until I add the l/s. Keep in mind that I have an aggressive tank. I just have a 7" mappa puffer in there now but plan on adding a harliquin tusk, Red lion fish and a eel.

 

[dburr]

Why would you seed the sand with L/S after 6 months of running? It is already L/S.
Corbon will leach out what it asorbed after a few days, I would change it. My .02

 

[puff(er) daddy]

I first started with cc then recently swithched over to sand about 1 month ago. I was told to change the carbon about once a month. b ball is saying to rinse it off once a week but not replace it, if I'm not misstaken.