Mate, water them not so often, i had some plants that would be overwatered if i didn't give them 5 days of no watering, time between each watering was 5days... seems long but it wasn't.
P.s. from this day onwards change to a 18/6 or 20/4 light cycle, trust me on this one and start doing it imediatly, i had this same issue, disapeared when i suddently changed from 24/0 to 18/6, some plants have so many generations of 18/6 cycles that once they get 24 cycle they can't develop well, its like if you as a human take 2h naps a day only, but a shark never sleeps, some strains are genetic sharks, while others are a fking panda and will need their sleep.