DWC plants in distress

First post here, hoping to bounce some ideas off more experienced growers. This is my first DWC grow, having done a few prior (with much success) in coco.

Running a Hubba Bubba Haze and a Mango Smile auto flower.

Week four feeding yesterday.

Noticed a bit of root rot at the end of last week and added some hydrogen peroxide, but otherwise they're fed the same this week as last week.

Up until yesterday they were thriving. This morning they have taken on leaf curl and discolouration. One seems worse than the other, though their feed is identical at this point.

It seemed warm in the tent this morning. In-house climate control did something weird last night and it is abnormally warm in there today. The water temperature in the buckets was 72F, working to lower that with containers full of ice now.

PPM perhaps too high at ~1100? Measured after mixing at ~950, so up considerably since then... which is weird maybe?

Confirmed that pH is still stable.

Heat stress? It's warm, but not hot.

The timing with yesterdays nute change seems suspicious.

They're under LED.

Any suggestions welcome and appreciated.

Just to emphasize, the discolouration and clawing came on within the past 24 hours. I don't have a "before" photo in the same lighting conditions, but here they are yesterday.

Thanks!

Still struggling to keep reservoir temperature down, but I cut the HBH nutrients from ~1000 PPM to ~800 and the Mango Smile to about ~900 and they both seem to be doing better this morning.

not sure if the decrease in nutes or the decrease in temperature that came with the water change was more beneficial, but the reservoir temp was back up to 71 F this morning and they’re both looking better than yesterday.

I’ll see how things stabilize over the next day or two and then look at re-increasing.