Help, please

[animallover]

Hi!
I have seahorses, coral, feather dusters, xenia, clove polyps, mandarin gobie, and an emerald crab. What should be my proper KH ppm? I'm not sure if my range should be in the 6-11 degree(100-200 ppm) or 11-22 degree (200-400 ppm)? I keep showing between 13-16 drops - is this ok? Also, I'm unsure --should my alkalinity be 6 meq/L or more or less? The following readings I took tonight:
Alkalinity 7 meq/L
PH 8.3
Ammonia 0 ppm
Nitrite 0 ppm
Calcium 440 ppm
KH 13 drops or degrees (232.7 ppm)
Salinity 1.025
****Nitrate 30 ppm *****
How can my nitrates be this high if all my other levels are ok? Any input, anyone?
I appreciate any response. I have only been doing this since last October--any other advice on what I have and need to do is very much appreciated.
It is all about my seahorse for me, so if I have to adjust anything, it will be in the best interest of my seahorses