I think I have a calcium deficiency and maybe nutrient lockout. What do you think? I’m growing chocolope, HLG 600 Rspec (horticultural lighting group) set to 15000- 16000 LUX right now, Fox farm ocean soil, I have the three foxfarm nutrients (Big Bloom tiger bloom and big bud) I have not been using those nutrients because the PPM coming from the drain is about 600. I made a rookie mistake in the beginning and forgot to add Cal mag so I’m pretty sure the brown spots are a calcium deficiency. I accidentally watered with the nutrients in the beginning 3 or 4 times… It’s been 20 years since I grew last time so I’m a little rusty. The PPM when I was watering with the nutrients was between 1200 and 1500… I know embarrassing rookie mistake. I planted October 5th of 2021, I do have CO2 in the 5x8 gorilla grow tent it’s always between 1200 and 1500 ppm, temperature is a steady 74 and the humidity stays right at about 50%. I would love for anybody’s wisdom on this because I’m starting to get frustrated. I haven’t seen a change when I added Fox farm Cal mag 1 tsp per gallon of water… As a matter of fact the more leaves are starting to look like that. Is it possible the nutrient lockout will stop calcium as well? Thank you in advance for your help!
Also I forgot to add pH is between 6.5 and 6.8 on the money.
Welcome to the community and I went through this moving outdoors to inside and like yourself many years between. Great medium and comes loaded out of the bag and will typically carry you to about week 4-5 with PH water only. I do see a calcium deficiency. The 600 run off meant their eating and nutrient time. The 1200 isn’t bad if you’ve added any supplemental nutes. It shoot for a 1000 PPMs with base nutes, the FF trio is notorious for having salt and minerals build up in the root zone creating lock out. They also recommend a flush every 30 days to prevent this. Correcting the deficiency will take a week or so show to improvement. I would start with 5ml of calmag with 1/2 strength nutrients and catch some run of for testing your numbers. Below what’s going in is good and proves she is eating. If it’s 300 plus above what you’re feeding. She is locked out and needs a flushing. I prefer to correct before flushing, this can also flush away the beneficial microbes. Keep me posted 
yep. And when u water to avoid a salt build up water the pot slowly til u get runoff wvery water like 20% runoff. Let so much drip from the bottom then catch some to check the numbers. But always give a water til u get runoff and the leave it til she is dry again. In ffof I had to do like every 2 or 3 days and by mid flower I was atleast once a day basically sometimes I’d get 2 days before waters good luck looking nice as of now so good thing u caught it before too late
Great advice from a soil grower, I grow in coco and as @Mark0427 stated to run off every time to wash excess salts away. On point 
I am nowmon coco best switch I did. Any issues r super easy to wash away and restart at the point needed. Way better smell in the grow room and all. I’m happy with the switch. Just need to get me a auto pot setup going for myself now.
Beat switch I made as well. Started with soil for a few, then switched to coco. Dead on with easy to correct any issues with the ability to water or feed to run off daily or several times if a flush is needed without soggy medium. With ya on this one