Does anybody know what this stuff is and how to get rid of it? It has appeared on everything in the tank. Removed it from the glass and used toothbrush on some of the
DIY rocks but not on the
live rock. It has been white not green and slimey feeling.

The alkalinity is low and calcium is high. Using reef builder to raise alkalinity.
all other parameters are ok
90 gal, 2-250
MH, 2
VHO actinics NO3 - 0
PO4 - <.1
NO2 - 0
NH4 - 0
PH - 8.2
Ca - 600+
Alk - 0
Sp gravity 1.025
RO/DI with <4ppm
TDS
Tank had only been set up 6 weeks and this showed up after 3
By the way I have been listening to the podcast and almost caught up now that I have a MP3 player. They have been very informative. Keep up the good work.