What do you think ?

[Yiss]

Hey might have know why your corals take so long to open. probably it might have nothing to do with the pest or water parameters. It could be your lighting.
Corals is best to be given white lights. Actinic blue is more for viewing pleasure and growing coralline algae


I am currently using full Actinic blue for my tank. Brought 2 colonies of zoos. 1 opened after serveral hours while the other still closed after 3 days.
Is it due to the lighting as being full Actinic blue ?

[jedininja]

For some zoos, actinic is not bright enough to trigger them to open. If you want the blueish look, I would add one 10k bulb to your setup.