GMSgrowsanswered grow question 3 years ago normal for soilless to get some brown in their tip going into flower. So many changes going into flower in soiless that this usually happens but it settles. if your still running 24 hours I would cut them back to at least 20/4 personally, so those buds get big. plants do a lot while they rest. check your runoffs waters ph and ec levels, I would try to keep it about 600 ppm and when you see flowers form, bring the ph up to 6.2