I don't see a problem. A lot of tank keepers would like a nitrate level at 20 ppm or under. I found small tanks to be a challenge. The water chemistry can change quickly, because there's not enough water in them to dilute a mistake in tank management. I have a 20 G long I've had running for a long time and change about 60 percent of the water in it every week, sometimes more often. I actually, replace the water often enough that I was able to stop testing it. I found if I kept flushing new water through the tank weekly, there was no time for nitrogen to build up before I removed it. I never let the fish know I quit testing their tank water, though.
Don't fret over the water's chemical makeup, just change half or more every few days to keep the chemistry stable and the fish and plants will be fine.
"Fear not my child, just change the tank water."