they are in 16 litre buckets and they are about 22 inches tall i lst'd them and each jh has got about 10 or 12 main tops and i'm scared to move them to re pot coz they'd snap as the branches are quite thin
Sounds like "Pythium" issues, there are around 7 types including Pythium, Verticillium, and Phytophthora, and Fusariuma aka root rot i had a simmilar problem wit the demonic fungacide in my DWC, also investigate ur water it may be chlorine issues . but it is true leaves do brown during flowering.. good luck hope u solve this issue out an have a good old blaze up