I have my GSP halfway up in the tank with medium flow and medium light. They are growing and spreading like wildfire. Mine will close up for days at a time though with no apparent reason but always open up eventually. Also, they close up when snails or hermits are messing around on it so that might be a cause as well.
180g Reef - 60g Rimless Reef -90G FOWLR- 125g Malawi Cichlids- 40b REEF- 34g Fresh Planted-working on- 20L FOWLR- working on
I have a mix of many different saltwater fish amongst my tanks, but I love my Tangs most of all.