my reef has been established best part of a year now and ive had more then my fair share of hicups (mostly due to hitch hikers) but always managed to find a answer in one of my many books or simply by self investigating, but this i cannot work out, my blue lights come on at 6am but unlike normal by 6:37 my water went very cloudy! i did all the useal checks my nitrites and nitrates and amonia everything checks out fine so i turned my attention to the filters, couldn't find a problem there either. now useally for a large tank a sudden change isnt so sudden 300litres but this was and i am out of ideas of what it could possibly be? any ideas of what has happened and how to resolve it (btw i do have a
skimmer and it is also doing its job)

any ideas or sugestions would help.. only think my head keeps saying is its possibly coral spawning? but i doubt this