I doubt the photoperiod is an issue. Low PAR is certainly a possibility though. I have Hammers and a Frogspawn under 300+ Par and a Torch in a 250+ range. Max Par period is 6 hours. They took a whille to adjust to those levels.
I don't think your inorganic N & P levels are an issue. I struggle with N. Nitrate usually about 2 ppm (Salifert). Phosphate stays at .05 to .1 ppm. The LPS don't seem to mind.
I noticed that in my mixed reef, the LPS didn't like the same amount of flow as the SPS corals. I created areas of higher and lower flow rates and experimented with placing corals in them. Invariably, the LPS did better in the lower flow zones.
You could be limiting available organic carbon (FOOD) in an effort to keep nutrients low. More fish and more food (more fish poop!) might be an answer to your problem... or maybe some hydrocarbon rich additive (like Reef Energy AB+) might do the trick You could even try target feeding the LPS corals.
I don't think your inorganic N & P levels are an issue. I struggle with N. Nitrate usually about 2 ppm (Salifert). Phosphate stays at .05 to .1 ppm. The LPS don't seem to mind.
I noticed that in my mixed reef, the LPS didn't like the same amount of flow as the SPS corals. I created areas of higher and lower flow rates and experimented with placing corals in them. Invariably, the LPS did better in the lower flow zones.
You could be limiting available organic carbon (FOOD) in an effort to keep nutrients low. More fish and more food (more fish poop!) might be an answer to your problem... or maybe some hydrocarbon rich additive (like Reef Energy AB+) might do the trick You could even try target feeding the LPS corals.