Is it rooted rot? ( more photos)

No its not. I have grown in dwc for around 3 years and come across this many times you will find over time roots will discolour they will go from milky white to a browny kind of colour and its completely normal. They just do it overtime. You are highly unlikely to get root rot in a dwc system one of the reasons I chose it in order to get root rot a bad pathogen would need to get into your res and your res is closed off so thats pretty impossible dwc is the best way for cultivation if you wanna minize as many pest factors as possible in my opinion and on top of this roots can be stained by the water in your res and this is completely normal and does not effect growth in anyway nore does the discolouration overtime its completely normal :) Another reason root rot is higly unlikely in a dwc system is the amount of movement in the res with the oxygen and surface distubance it would be highly unlikly anything bad would be able to settle in the water because theres just too much movement.

Hi mate, looking at your diary you haven't mentioned anything about your solution temperature. The temperature of the water is very important if you want your roots to absorb nutrients and oxygen. You can put as many air stones as you like in a reservoir but if the water is too hot you roots cannot absorb oxygen. If it is too cold it struggles to absorb nutrients. I reckon you have had more warm days than cold and this is the result. Some of the roots seem quite healthy so i hope this helps, good luck and happy growing