Help, invert dieing and small pink granules floating everywhere

[utreefer]

I woke up this morning to find my tank full of these little pink granules floating everywhere. They are about the size of fine sand and the color of coralline algea.
As of 1hr ago my snails have started falling off my glass. I assume they are dieing. MY crabs seem to be fine.
Nitrites 0
Nitrates 0-5 closer to 0 than to 5
Ammonia 0
Temp. 78
salinity 1.024
All fish and corals seen to be doing fine. However my Zoa's don't seem happy. The only thing that has changes is my clam mover over really close to one group of zoas.

 

[utreefer]

A couple more pictures with my water flowing.

 

[utreefer]

I put my filter sock back on and it has captured most of the granules. Still curious what they are and why my snails are dieing. I have 3 snails that look fine and 15 that appear dead.

 

[slice]

You didn't mention your pH, any wild swings?
Are you dosing anything that could be precipitating?

 

[utreefer]

I forgot to check my pH. I haven't dosed anything within the last couple of weeks. Last thing I dosed for was calcium. It was down around 350.
pH is higher than 8.3 but lower than 8.6 according to my Salifert test kit. I will check my calcium and alk next.

 

[slice]

OK then, you have reached my level of competence. (happened real quick, didn't it?)
Hopefully someone will know how to advise.

 

[utreefer]

Calcium 430 -450
KH 110mg/L (my test kit said ideal was 150mg/L)
I usually keep my temp at 79 during the day 77-78 at night. When I checked it this morning it was down to 75. I am in the process of raising it back up to 79-80.

 

[utreefer]

I guess no one has run into this issue before?

 

[ppanthrah75]

ive never heard this have u tried googling it? im curious myself

 

[spanko]

the pink "granules" may have been the sun coral releasing larvae.
http://www.marineaquariumsa.com/showthread.php?t=17421

 

[utreefer]

Interesting. I suppose that could have been what it was. I look for new polyps popping up. I don't know many larvae are produced and how often, but there must have been a couple hundred and my wife said it happened a couples days later. I was up snowboarding and by the time I got home my filter had cleaned them all up.