Its my understanding that
NO3 levels don't become a major concern until atleast 50-80ppm, though most agree that 40ppm or less is ideal for
FW and it can be lower depending on the type of fish/invertebrate.
Excessive
NO3 can supply extra nitrogen which can contribute to algae blooms.
My 75gal consistently runs 40-60ppm
NO3 (I don't worry about it, messy fish

), while my Bettas 10gal tanks run 10ppm
NO3.
I would also make sure your not using a testkit that measures
NO3-N (nitrate/nitrogen), as it will give readings 4.4x's less
If you ran the cycle and
NH3 and
NO2 have zero'd and
NO3 has spiked, then your cycled... I would start adding fish
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