Coco grow: Magnesium def, right?

`Yes? Well as I red, classical symptoms of Magnesium def (green veins, yellowing leaf, stunted growth, curling)...She is 3 weeks old from sprout and new growth yellowing. Coco with perlite, PH`d water 5,8-6,4 , hand watering every day until some run-off, Canna coco A+B 2ml per 1 Liter, 1 gallon pot. Also LST`d , tied down.
The other sister is exactly on same diet, is 4 weeks old and is twice as big, nice and green (in 3 gal pot), and getting ready for 12/12...

Also fed her Epsom salt 0,75ml per 1L of water, twice, doesn`t seem to help...

Or maybe the big question is: if epson salt cure works only if dosed as foilar feed?

Your using nutes every watering?

Yes indeed

Magnesium def signs - purple veins, leafs rolling to the left or right, or leaf tacoing. Magnesium issues usually arrive when you over water your plants, your roots need a dry time, so everyday watering is sort of excessive for coco/perlite blend. by the looks of your new growth, it looks like over watering is happening with the inter leaf spacing swelling up like it is.

Yes, thought about over watering myself. I guess plants are different, as her sister doesnt mind everyday water. She is on 2nd day dry period now. Would this be enough to help or should I foliar feed her too?

when i grow coco, I do a 3 day cycle and seems to work for me....3 day cycle is; day 1 feed with nutrient solution with calmag, day 2 is a watering with just calmag 300ppm, and day 3 nothing, then repeat the cycle