it looks like your pH is too low. check the pH of your runoff water. let us know the pH of the water you put in, and what comes out. optimal hydro pH ranges (5.5-6.0) apply for coco coir.
Ok i dont wanna seem like a prick today but here it goes anyway. All ur different things are at different pHs. Your water, nutes, runoff, and soil. The thing is your runoff is an indicator of your soils pH maybe. That doesnt give you a real acurate # of what ur soils pH is. So again, check your SOILS pH and go from there.
I didn't take that as "dick move" I'm a noob so any info is helpful and I water once every two or three days in coco...
welp turned out it was heat stress, moved the lamp and turned on a fan or two..seems to be doing better