New to Saltwater - Water Chemistry

[Young@Heart]

Need some advice:

I have a 55 Gallon Tank (no Sump). I use 2 75 Gallon Aqueon HOB filters and approx 38 lbs of live rock for filtration.

Population:
2 Clownfish
1 Sleeper (sandsifter) Goby
3 Emerald Crabs
1 Pigmy Angelfish
1 Gorilla Nipple Coral
1 Kenya Tree Coral

I am using RO in my tank. Tested parameters:

Temp 78.5 F
Salinity = 1.0245 to 1.025 (A refractometer should help pin this down)
Ammonia = 0 ppm
Nitrite = 0 ppm
Nitrate 5-10 ppm

Because I am new to some of this, I was feeding each animal just about every day - and this put me into overfeeding - I have reduced my feeding to about 7.5 ml of Mysis Shrimp once per day, but my Nitrate level still seems to be around 5-10 ppm. I have been told this is to high for corals. I am concerned with the 2 I have and I have 3 more on hold The ones I am looking to get are:
Gorilla Nipple
Fancy Zoa
Fancy Chalice

I am using the API Saltwater Master Test Kit and a Hydrometer. But I need some direction on my Nitrates. I have 1 LFS telling me my Nitrate level is to high and another saying it is not bad. From what I have been reading the level I am testing at is not bad. Please help and clarify.

 

[Waters]

Your nitrates are fine.......coral require some nutrients in the form of nitrates and phosphates. If you can keep them at the level they are at now, you will be good