Plant deficiency? Leaves browning...

I have seen signs of brown spots for a few weeks now. Any ideas what this could be?

Notes:
- they've been in flower 2 weeks
- nutes were floranova and cal/mag to 1300 ppm at .5 conversion
- ro water
- 1000w hps
- dwc

I just switched to Lucas formula today, 8/16 micro/bloom with no cal mag...see if that helps. I have an intake into the Mother room then a hole up top that feeds into the grow room. The exhaust pulls air out of the grow room. I was wondering if the grow room could be lacking fresh air. The temp goes up to 28 Celsius.

Another pic

Looks like a Calcium issue to me, were you giving above the recommended dosage of calmag?

Kinda, I was guessing at how much water I was putting in to top up the buckets but I just marked out the bucket so I can get more accurate mixing... may have been a little bit light, thought I was playing it safe.

Looking at this leaf in the first image, white widow grown in a pot, deficiency of a chemical most likely. First grow, plant seems happy & healthy till this. It's time to harvest soon as it's getting cold in southern Ontario so no biggie I'd say. But obviously somethings missing. Calcium? Next grow I'll study nutrient feeding more closely. I did fertilize with 18-24-16 three times when the roses in the garden where gettin it. Lol Pro mix (vegetable /herb formula) soil was the base.

Could it be too hot?

Magna83 said:

Could it be too hot?

Click to expand...

Doesn't show that!

Brown necrotic spots = Cal def.

If it stops progressing your good!
How does the new growth look?