Help me identify and fix this problem please!

[BeenSmokin_NewToGrowin]

Can someone please help me identify and fix this problem? I’m new to growing and I’m not sure what to do. My temp is 86f, co2 is set at 1300-1400 ppms, water temp is 68f, ph is 5.8, growing in rdwc. Using hlg650r and lamp to plant distance is 36 inches. Someone please help. Thanks!

 

[Phytoplankton]

What are you feeding? At what PH and PPM? (or EC). Just offhand it looks like it could be a potassium issue, or it's a burn from to many nutes, need more info.

 

[Boatguy]

Can someone please help me identify and fix this problem? I’m new to growing and I’m not sure what to do. My temp is 86f, co2 is set at 1300-1400 ppms, water temp is 68f, ph is 5.8, growing in rdwc. Using hlg650r and lamp to plant distance is 36 inches. Someone please help. Thanks!

Why is your hydroton so dry? What kind of grow is this?