First Time SPS need help

[bunzaroo]

My tank has been running for about 15 months. It is stocked w/ 4 fish (2 clownfish, yellow tang, blue devil damsel), My tank is pretty well stocked several LPS, NPS softies, a couple of clams, 1 sebae anemone, etc... I run an Ice Cap Overdriven 48" T5 setup. I do not dose anything, I use r/o water. I do 15% water changes every month. I want to start keeping some hardy SPS in a space that I have reserved about 1 foot from the lamps. Anybody have any suggestions for some good looking, but hardy SPS. I dont' want to start dosing Kalk or anything like that for now. As far as flow I have about 20-25 turnover. Thanks in advance.

Nitrates 10
Ammonia 0
Calcium 520-540 Kent Sea Salt
PH 8.0-8.2
Magnesium - Do not test
Salinity 1.026
Alk 8

[coral_lagoon]

The branching digitatas are pretty hardy. With that being said, you should start thinking about dripping kalkwasser if your going to put sps corals though. Kalk, or at least the two part stuff..