Oh gosh. API tests can be vexing. For pH, I will say... midrange or higher.
Ammonia: might be .25 or a bit higher. Often API reads .25 instead of 0. You might want to try just freshly mixed saltwater to see what 0 looks like.
Nitrite: easy 0.
Nitrate: 5-10.
Phosphate 0 but that test is not sensitive enough to be practical.
Take the silly gloves off, and throw the API in the trash. API do not test anywhere near the levels we try and keep in reef tanks. They are fine for a quick check, but if something is amiss, you need more accurate kits. Better to just run a test with a better kit IMO.
I second Homer's post. I threw away my api calcium kit and went with salfert, haven't looked back. My brother in law was chasing his tail for a month on a new tank set up until he finally ditched the api kits and went with another brand, found out his tank was just fine and on the numbers for a new set up.
Just had an experience with my kit. Nitrate was always 0. Loosing corals left and right for couple of weeks. Took water sample to LFS and it was 100ppm. Left the LFA with a different kit.