For the last two days one of my crocea clams keeps spitting up cloudy white stuff. It does it about every 5-10 minutes and now the whole tank is cloudy with what looks like tiny air bubbles. I just added some Seachem reef advantage calcium yesterday, but only half of what was recommended. There's a total of 3 clams in the tank but only one seems to be throwing up. Has anyone else heard of this before?