Help with Nitrates

[Subliminal]

80ppm is dangerously high. What test kit are you using? How are your fish acting?

I would invest in one of these if I were you:
http://www.drsfostersmith.com/Product/Prod_Display.cfm?pcatid=3618&N=2004+113080

It will lower your nitrates a lot.

While I just purchased one of those and am loving it on my 29g, I'd question whether a HOB fuge would be large enough for a 90g tank.

 

[SHK_ATK]

agree with getting a refuge, they are amazing for keeping ates down plus you can always put something bothersome in there, ie mantis shrimp or a big @$$ hermit.