One Plant has yellow on the edges, the other looks like it's dying

These are all 3 weeks old from sprout. They are in half fox farm ocean forest and happy frog. I have used no nutes on them, I only water with distilled water thus far, and I water once every 3 days.
The one with the yellow edges looks good otherwise.
The one that has the ends that are dying and the entire plant is sagging, I have no idea what's going on with it. They're all automatic feminized plants.

Looks like you once had or still have some heat issue I also think you have some ph issue little dolomite lime would fix that

keep it real. said:

Looks like you once had or still have some heat issue I also think you have some ph issue little dolomite lime would fix that

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Temp never gets above ninety and the pH is 6.5

more likely the ph issue, im my experiences with happy frog it was a bit too acidic. yup dolomite lime

your temp shouldn't go above 85, and are you using a ph meter?

ROFLhacks said:

your temp shouldn't go above 85, and are you using a ph meter?

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Yeah, I use my pH meter, it was 6.5 in all 4 plants soil. I may just turn the MH down to 75% on my ballast and ease off on the watering. It looks like it has signs of overwatering to me. The slight yellowing on the leaves of the other I am not sure what is causing that, the leaves are standing strong.

over-watered...............................................clear cut,imo

yup, you have to let your medium dry out completely between watering especially with happy frog.