HELP! Unhealthy plants

[Skuxas]

Hi team,
im a first time grower in Western Australia, ive had no real issues until now, two of the three plants are looking sick. The lean one has dropped all the big fan leaves and the only good looking leaves are the bud sites the rest looks like its about to die. The shorter light green has badly damaged leaf tips. Then the third xmas tree looking one is perfect. They all have the same routine. Id say im in second week of flowering. They are in all day sun and its sunny here everyday and has been hot for the last month or so.
i water every second day used powerfeed red bottle for vege then now use biocanna bio flores.

please help im lost

[Rwise]

W.A. is noted for being hot, like 40-45C Hot, OUCH! I do see heat stress, can you shade them part of the day?
I also see hot soil (to much feed) as the tips have burned. With flower food now that should change (tips will not grow back).
PH? If you dont have a tool for this, get one please.
Autos or photos? Most autos will not like the heat.
If green leaves can be puled off with a gentle tug, they need more water regularly.
Hit the link at the top of this page "Plant Problems" this info will be helpful.
Water source?

[Skuxas]

Thanks a lot for your comment, i have moved the plants so not so much sun. I have ordered a digital ph meter so hopefully get some better results. What ph is ideal for the stage of growth do u think?

[crazyplanet]

The tips have burned. Have you measured the ph of the soil? Maybe the temperature is a little high

[Skuxas]

What ph is ideal?