Ok... I didn't read the result of your test correctly...
Reiser is absolutely correct... your sps are not thriving because you have no nutrients...
it is that simple ...
You are afraid of algea issues aren't you?
You can't have sps without a little nutrients...
If you don't want fish, I'd get some Fauna Marin amino acids - Amin (there are many good amino acid supplements- I just mention Fauna because you are already using some)
Also, maybe a good vitamin mix like AF Vitality..
Also, Fauna's new MIN S would also benefit your tank... you need some nutrients in there!
At the same time, get a ton of snails, hermits and maybe an urchin and don't let fear ruin the hobby for you!