A few of my plants are starting to het these yellow leaves Idk what to do, I water them with 6.0 ph and they are under a 1000 watt led light

Looks like light stress but if you can get the pH and PPM runoff measurements it may uncover info leading to something else.

Definitely looks like heat stress to me I had the same problem raise your light to about 24 inches see if that helps,is your tent hot do you have fans and ventilation in

Try to get closer to 6.5 to 6.8 if possible

What is your ph and ppm runoff are they auto or photo how old what kind of light what are you growing in,is going to be needed for the community to help,I'm a newbie how close is your light kinda looks like heat stress try to get a better pic my friend