spotting on leaves, nutrient deficiency?

[QuentinQuark]

Hi folks,

I am in week 5 of an 8 week flowering cycle. This is indoor, sort of following Al B Fuct for perpetual SoG, but doing DWC instead of E&F.

My pH is quite stable, I check it daily if not twice daily, never outside of the 5.5 - 5.8 range.

Temperatures are also quite stable, 18c (65f) during lights out, 24c (75f) during lights on.

Humidity stays between 35% and 55%.

I run a sulfer burner every 3 or 4 days, for a few hours.

I am flowering under 1000W HPS.

I don't know what my ppm is, but I know I am going quite light on the nutes because I don't want to burn. This is a perpetual grow, so I would rather increase the nutes on the next cycle if necessary. That's why I'm pretty sure it's a deficiency and not burn, the nutes are way too low to cause burn.

If you can tell me what the issue is with these girls it would be much appreciated!

Thanks!

 

[CanadianBacon]

Looks like possible lack of potassium if its not heat stress or nute burn

 

[QuentinQuark]

It's a perpetual grow, so I upped the nutes on the next cycle. Anyone else think they know what this is?

 

[nraged]

Imo it looks like a calcium or manganese defeciency.

Comparing to pics from this link
http://420magazine.com/forums/frequently-asked-questions/81266-cannabis-plant-pest-problem-solver-pictorial.html

those are the two that look most like your plant especially the second picture of your post. Thats the best link i have found so far when trying to self diagnose plants.

 

[Topher89]

Hell of a link, that guy put some time into his tutorial. Everyone should read what nraged just posted.

 

[nraged]

Hell of a link, that guy put some time into his tutorial. Everyone should read what nraged just posted.

The founder of the magizine wrote that so I figured the knowledge is legit and the time spent writing it to help us in need much props to the man for looking out.

 

[QuentinQuark]

Confirmed, this was a calcium deficiency. Corrected with 200mL of CalMag in 20 gallon tub.