In case you guys have not come across this article... It is a great read for SPS growers. http://www.reef2reef.com/threads/help-my-sps-are-paling-and-i-dont-know-what-to-do.210035/ General summary: -Keep Nitrates above Phosphates -GFO strips out more than just phosphates (minerals, etc) and requires a follow up water change to replenish lost minerals. (So don't use GFO) -add potassium nitrate, sodium nitrate, or calcium nitrate to dose nitrate. -SPS needs nitrates and phosphate to grow. -browned out SPS means too much nutrients, not enough light. -light/pale SPS means not enough nutrients, too much light. -macro algae love nitrates, so do the symbiotic plankton in SPS. -first dose of nitrates will need to big larger amount since your tank will soak it up. -minimize pellets (except to use it to add phosphates) -bio-pellet and carbon dosing remove nitrates faster than phosphates, so it leaves you with low nitrate, higher phosphate ratio over time. This is bad for SPS growth. (So stop use of fast nitrate removers - i.e. Stop carbon dosing and bio-pellets).