Leafs yellowing

[BegginerGrower]

Does anyone know why my leafs are yellowing? Manly at the top of the plant but In the middle on 1 plant, they're 3-4 weeks in flower,theyve also got some burn tips.. I'm growing on coco, EC 1-1.1 PH 5.8-6.2 was using 1/3 strength general hydroponics so lowered it to 1/4 at, the odd plant is also getting small rust marks,they're auto flowers by the way..they're in 10 litre pots so this morning I flushed them all with each 30 litre of plain water ph'd at 6-6.2 then a once drained I gave them each 1 litre of 1/4 solution EC 0.8 PH 6.2 when should I next feed them?

 

[GrassBurner]

Make sure you don't have any bugs. Check under the leaves good. I had thrips that killed a bunch of my leaves before I got them.

 

[BegginerGrower]

Make sure you don't have any bugs. Check under the leaves good. I had thrips that killed a bunch of my leaves before I got them.

Definitely no bugs, I had this problem at start of the grow then it stopped,think it's cause of changim the amounts of nutrients when they went I to flower

 

[twentyeight.threefive]

You'd get more helpful replies if you took pictures of your leafs and whole plant with the lights off. Everything looks orange.

 

[Bigby]

Worrying about little issues like that is a pointless stress in my opinion. Often trying to correct minor issues which are not a real problem can lead to a real problem. From what I can see of those plants they look generally healthy. I've got a super feeding Yumbolt Banana here which is taking twice as much feed as anything else in the tent. She's been losing leaves to yellowing no matter how much 'grow' i give here - nothing to worry about though, she's still gonna finish and yield well. Peace.