The water on Ramlet el Baida turned green in the last few days, not due to some chemical waste, but because of the increase in temperature and a rare bloom of marine phytoplankton. The green color is expected to last at least few more days and it’s a natural phenomenem that shouldn’t stop you from hitting the beach. Someone should go check if they glow at night.
On the other hand, the beach at Ramlet el Baida is not safe for swimming in the first place as far as I know and I wouldn’t risk swimming there whether it’s blue or green!