Planted Tank Guru
Join Date: Dec 2017
Location: Elk Grove, California
Neon tetras are endemic to waters that are soft, acidic, with little dissolved organics; so, yes, I would do a water change.
I would let 20 ppm be my guide to when to do a water change or just do weekly water changes of at least 25% and see where you are each week and adjust frequency and volume from there.