ohx.. duno leh my corceas have been doing well in my tank for several months already... my lighting is abt 36 watts.. consist onli 2 clowns and cleaner shrimp.. recently brought 2 star fish.. one of it is sand shifter... another one is, having veri long and spikes legs.. black in colour.. i got it from a LFS shop and the person told me is also another type of sand shifter and reef safe.. no idea about it.. now i tink my PO4 is increaseing.. duno why... resulting in alot of red furry stuff on my sand bed and liferocks.. got ani idea how to remove it?