Pics inside! Cal/Mag def in flower stage?

[novapants]

Here we are, 3.5 weeks into flowering and I am getting the issue of yellowing upper leaves accompanied by brown spotting within those leaves. Some leaves are green w the spots so I'm assuming the yellowing ones are the more infected.

Some background:
Strain: nirvana northern light autoflower
Lights: 250w HPS. 2 65w CFLs
Soil: ffof
Nutes: fox far trio, supplemented dolomite lime for cal mag boost
Light schedule: 18/6
Temps: 70-81 F
Humidity: 35-42%
Ph of soil: using the drop method with runoff I get a solid 6.0 reading

I always test my water ph to around 6-6.5.

This is my first grow n I believe I'm halfway into my flowering stage. So not sure if I should just ride the next 3.5 weeks out or find a solution.

Look at the lower left leaf for spotting/yellowing

spotting/yellowing in newer growth

Top of plant has twisty new growth(only 1 of 3 to have twisty growth like this)

 

[Waira]

Hi Nova- It's hard to tell in these pics, because I can't enlarge them... can you reload them another way? (go through the File Upload Manager)...Or better yet, shoot us new ones in reg lighting-- HPS light color spec' interferes with greens and browns, critical for diagnosis!,... from what I can tell, there's Ca defc. happening, maybe some N defc. too,.... possibly others, but I'll need regular light pics, and leaf close-ups as well, please.... details are everything when diagnosing,... ***.... dolomite isn't very fast acting, so it's very possible to have Ca-Mg defc. issues even when the soil is amended so,... Get us fresh pics please, and we'll sort this out, mate!

 

[novapants]

 

[Muddy]

Most likely you're in nutrient lockout from your pH being too low. If you're feeding at 6.5 and getting run off of 6 your actual soil pH could be down around 5.5. Anywhere below 6.5 cal and mag started to become unavailable. At 5.5, both phosphorus and and potassium are also locked out. This late in the grow adding more lime won't really be effective unless it's hydrated lime. Dolomite is too slow acting, taking about 2 weeks to start working. I would suggest raising the pH of your feeds to 7.0 which should raise your run off to around 6.5.