Are you using test strips or liquid test kit? The strips (I usually had great success with them UNTIL I didn't and lost almost an entire 35G community of fish due to bad reading/inaccurate strips,) can be inaccurate.
If you normally do a 25% weekly pwc
, I would do 50% pwc
BUT if you almost never do a pwc
then I would do a 25% refill, and another 25%. See if there is any change. If it seems better, I would do a couple more back to back 25% pwc
Do you know if the tank is cycled?
Are you using the same filter from the previous tank? If so how long?
Is it brand new filter pads/media? If used was it cleaned with untreated water from the tap?
Watch for Ich, if no change. Ich can be present before you SEE it as spots. FYI.
Also see if you see any tiny worm like things in the gills or body or anal vent.
to back would do a couple