well, it looks like you have most things in order...
make sure you are not using any BIO media in the canister, that WILL cause
nitrate issues.
and yes for the test kits, if they are salifert, you are reading them right.
the
skimmer isn't really a good
skimmer from what i have heard, but i have never used one, so i cant speak from experience.
just keep going with the water changes and reduce your feeding amount of frequency and see if the levels start to drop.