upgrading tanks?

yea my bigger pieces of argonite always got coraline on them, i was so sick of coraline after that tank, last thing i need was purple flecks on my sand.

a few kinds can still grow on the fine(diatom still might altho im not sure if its just resting on top) kind but not as much

 

Yes, take the CC out and run an aragonite sand. I personally prefer the carib sea special reef grade sand as it does not get stirred up as easily as the really fine stuff. It is still safe for soft bellied critters and burrowers.

I ran my old 35g with CC for several years, and the detritus that got stuck in between the CC made problems for me.

The CC is good for making your own LR or for a calcium reactor media, so don't throw it out, but do wash it before storing it.

 

The diatoms are just resting on top. What you see are dead carcasses. Those aren't alive.