yes,
nitrates are ok and helpful to certain livestock in trace amounts.
but anything that can be detected with a hobby kit is "technically" to high.
will the tank be fine? sure.
"most" inhabitants can survive with a
nitrate levels up to about 5
ppm, but that's not optimal.
if you are reading 5, you should work to reduce it, but not freak out as you should if you read 10, 20 or more..
two points i want to make.
1.) you "can" achieve 0
nitrates.
2.) Gwen is right that most tanks will do just fine with a reading of <5ppm
nitrate, but you should still work to reduce.
once you get into the more advanced invertebrates, then even 5ppm of
nitrate "can" be too high.