High nitrates in a planted tank?!?! Theres something wrong. How many plants do you have? How are you stocked? Could the nitrates be comming from the tap water?
Who lives in the tank and what kind of feeding schedule are you on?
Also, what's your lighting situation like and what kind of plants do you have? (If your plants don't have enough light they won't grow enough to consume nutrients).
I wont have lights until I get paid next. I am what you would call a "starving student". Slow accumulation of aquarium goodies is really my only option. My tank is okay as far as amounts of fish and feeding schedule. All of my other parameters are perfect.