Your calupera went sexual. This is why you leave the light on 24/7.
Hope you have some polyfilters around. Use charcoal, or whatever you have.
I agree with Beth, large water change and filters.
Good luck!
Definitely sounds like your caulperas went "sexual"...(turns white/sort of melts away/releases spores through-out the water system/means of reproduction)...Without specific info on your system I'd say run poly filters and carbon...personally I'd avoid drastic water changes...maybe about 5% or so every few days for awhile until things settle...do you run a skimmer? A good skimmer can help remove the spores...combined with good mechanical filters.
As mentioned running lighting over caulperas 24/7 can prevent such problems...but in my opinion your situation is not "fatal"...just try to remove the "cloudy" stuff from the system as rapidly as possible...and in the future take steps to prevent a repeat.
The main danger of caulpera going sexual is the release of nutrients back into the tank and lack of oxygen. If you have a good skimmer I would only do small water changes and test. Test all of the usual parameters and keep a close eye on them. In my personal opinion I would avoid doing a large water change. New water while not having any of the harmful nutrients also removes beneficial microbes and is stressful to the tanks inhabitants.