Is this a calcium/magnesium deficiency?

[Tal420]

I'm growing indoor this Lemon Orange from Greenhouse, in BioBizz lightmix soil, BioGrow/BioBloom/TopMax nutrients and it just finished the 3rd week of flowering. She's in a 50ltr pot and drinks 8ltr of water every 3 to 4 days, ph 6.7.

Last week I started noticing some brown spots on the fan leaves in the middle of the plant. Thinking it could be a Magnesium deficiency I have added BioBizz CalMag to the last feed, 1ml/Ltr to be precise.

Tomorrow is the next feeding, however I'm not sure if I should keep adding CalMag as I have noticed that the brown marks are moving to the upper leaves so I'm not sure I'm addressing the correct issue.

Here are some pics of the plant and the effected fan leaves.

Thanks.

 

[Phytoplankton]

It’s definitely the beginning of either a deficiency or lock out (not familiar with the nutes, are they organic?). I’d start with a minor change, try dropping your nute ph to about 6.2 you’ll get better absorption of cal mag.

 

[cbdhemp808]

I think it's calcium deficiency.

 

[Tal420]

It’s definitely the beginning of either a deficiency or lock out (not familiar with the nutes, are they organic?). I’d start with a minor change, try dropping your nute ph to about 6.2 you’ll get better absorption of cal mag.

Thx for your reply. Yes the nutes are organic. Will try lowering the pH to 6.2 today.