Drooping leaves on one ?? all my other plants are fine ?

ok so i have 4 plants exact same clones exact same growing method nutes etc... but one seems to be struggling? it has drooping leaves around the bottom and is basically shorter then all the others kinda stunted ?? any one help ? My room has been touching 30-35C the past few days due to the weather ! its meant to change on Tuesday so after that it will be back down to 25.

Looks overwatered to me, you got holes in the bottom of your container? And yeah those temps (usually 90+ F) will stunt growth...

its a DWC Setup sorry forgot to mention that the heat has been a problem the past couple of days that my be whats causing it

Normally if it's a heat problem the edges would be curled up. That drooping is normally a sign of overwatering.

the room being this hot has also caused the water temp to rise alot ! the water temp is 28c iv read anything above 21c can cause root rot ? should i be cooling my water down ?

Are your roots healthy and white?

yeah roots look fine atm just getting a bit worried i brought some h2o2 today gonna put some in later to keep them healthy

I have just had this situation in my own DWC grow. 2 plant same strain, one drooping, one not.
Last night when I was doing a weekly change i broke one of the airstones.
I didn't have a spare so i just put it back. this time though the air was bubbling like a volcano.
Tonight the plant with the droopy leaves and generally sad looking was much more perky and happy.
Its obvious now but I didn't see it before. Before the plant got more air it DID look like it was over watered, but
although it was in DWC, a bucket full of water, the plant was drowning for lack of oxygen.
Just like an over watered plant in soil.
Hope this helps.