There is nothing difficult about keeping SPS.
Strong lighting, good flow and and a big skimmer is the key.
High nutrient import and high nutrient export is a must. Water too dirty will make your SPS brown. Too clean water will make your SPS go pale, bleach and eventually die.
The key to water quality is stability.
Ca 380-420
Alk 6.5-8.5 DKh
Sg 1.024 - 1.026
Now by following the above water parameters, it does not mean that you should let your alk fluctuate from 6.5-8.5 dkh, it means choosing a number in that range and holding it there.
You cannot allow for the parameter to swing. Ideally to keep these parameters stable, a Carx or dosing system should be used so that dosages are constant and not a sudden daily dump of Ca and Alk which will cause parameters to fluctuate.
Remember SPS does not only stand for "Small Polyp Stoney" but also "Stability Promotes Success"