Yellow tips on newer growth - Please help

[Legal80]

I have yellowing tips on the very top and my leaves get crisper the further down you go on the plant. PH is 6.3 and I had a nute burn weeks ago. I feed them with distilled water and add calmag+ every third watering. It's on 24 hour light cycle, might be heat stress and magnesium? I usually give it a bit of runoff when I water the plant. The other plant in same setup looks pretty good but it still has some yellow tips on the top of the plant. I transplanted a couple weeks ago to this 5 gal smart pot in fox farms ocean forest. It's about 73 to 75 in grow room with fan, co2 bucket, 600w mh.

 

[Duncan Dehaviland]

You know, as great as FFOF is, the problems that keep cropping up for me, has to do with the nutes in the soil. My first burn withe FFoF came by the mistake of putting my plants on a feeding schedule too early. I learned to wait at least a month introducing nutes, giving the plants time to take in what's provided in the soil.
When I saw the next crop had signs of nute burn, I found that my using plain, distilled water and not testing it was a mistake. I figured since it was neutral, it would naturally complement the nutes already in the soil. That's when I learned that distilled water holds its ph of 7.0 until it's exposed to the air, and will drop to a ph of 5.0. A low ph has the same potential as a too high ph to bring a 'lock out' of nutes. I now keep the distilled water sealed until I'm about to use it. Then, there's always the reality that the plant itself may need different kinds attention.
I'd check the runoff to see if that might have anything to do with it. Other than that, your plants look great. How old are they?

 

[kamiljayah]

They look pretty lush.

 

[Legal80]

I found out I had a fan burn out on me. I fixed it and they recovered beautifully after a watering and a nute feed. I'm introducing LST a little late. This is my first grow so some things aren't planned. I just realized LST is pretty easy and I want the added yield so it seemed like a no brainer. Thanks for replying guys. I'll send some updated pics later today.

 

[Legal80]