[Delphinus]

Hi Dez,

It's hard to say. Sometimes coraline comes and goes. If there is a lot of calcium draw in your tank, it is possible that the coraline is simply being outcompeted.

Other possible causes are wild swings although I doubt high phosphates could be your cause. I know for sure nitrates do not impede coraline growth; my tank with the fastest coraline growth has had nitrates at times >60ppm and still no coraline bleaching.

Temperature swings could potentially be a cause though. I've also had coraline die off after a water change; and sometimes during the water changes any coraline exposed to air at the top of the tank turns white even after only a few minutes of exposure.

PS. Not that it really matters, but typically when only 12 hours has transpired and only one other message has been posted to the whole forum during that time, it typically isn't required to "bump" the message forward. Besides, if people have any sensibility they should be outside today enjoying one of the last weekends of summer with this awesome weather, so give them some time to respond. Just my $0.02... YMMV. ;)