Can you diagnose this problem?

[Jordog05]

Hi all, thanks for reading. My plants are roughly 4 weeks old, grown in coco coir/perlite/clay balls.
I'm still using 1/4 strength nutes.
They have been developing spots or marks on the leaves, and I'm completely unsure of the cause.
I've attached some pics to take a look at. Any help would be greatly appreciated.

Cheers!

 

[Chris Scorpio]

What's yer water pH at

 

[Jordog05]

Been feeding at 6. Haven't tested runoff though.

 

[Chris Scorpio]

I'm not sure but am thinking pH or Calmag issue , is it RO water

 

[improvise]

Cannabis Plant and Pest Problem Solver - Pictorial regards

 

[Jordog05]

I'm not sure but am thinking pH or Calmag issue , is it RO water

Yeah, I've had the same response on other forums. I'll test the run-off, adjust accordingly and up the Cal/Mag. No it's not RO water, but the water in Melbourne is really good... like the opposite of LA water.

Thanks for the input!

 

[Calvados]

Great link.