Fan leaves dying after flush.

Day 42 in flower growing in coco with perlite 25%. Sunleaves coco fiber brand never flushed it..
Using Floranova Bloom + calmag. After I decided to flush at day 40 the fan leaves are now drying up to the crisp curling up and eventually falling off..that bad. Rust spots on leaves. FNB has 4.0% calcium and 2.0% mag and FNB is pretty much loaded. After the flush I did not add any nutes I let them dry out for 5 days in plain water, and I never check my PH and I know everyone you can flag me. Next grow will be better (adding RO and coco specific nutes and hopefully will start to check PH).
I know its tough to work with nutrients that are not specif to coco, as coco has its own characteristic liking.
That is why next grow I will be going with Botanicare CNS17 for coco, I read some good sutff. Or Canna of course but will need to do more research.

you have nuts. burn and what leaves that were damaged will die even after you fix the. after you flushed and you fed them was it at 1/4 strength?

Could it be too much calcium? I am using tap water
PH lock out causing all kind of def..

If that's the most damaged leaf. It is not Nute burn. There is no classic leaf tip burn. Given how much damage is there, I would have expected half the leaf tip to be burned or so.

honestly I am unfamiliar with soilless mediums such as coco... What I do know though, is it is easy to lock out calcium and mg if your ph is not correct.

my diagnosis: cal mg defeciency.

Check your ph. ph is correct for coco is 5.4 to 5.8ish. I would like to assume that even though your adding cal/mg, it's being locked out due to your ph level.

also what kind of water are you using? Tap water? Or distilled? I only ask because I am curious why you started adding cal/mg in the first place? Plain water tap water should have enough, no?

IMO- Don't worry about the Fan leaves, there going to die, and fall off anyway.
If the rest of the plant looks good don't worry about it.

Good Luck on Your Grow