Can't spot issue

Havnt had this happen before. Several harvests but the issue is the leaves half of the leaf finger turning yellow with some spotting. Can't seem to find similar pictures. It starts with half of a finger then spreads from there. Not sure what to supp.

Leaves will eventually become brittle even while still green. Using maxibloom with tap and pH at 5.6

Stopped measuring ppms and such a few harvests back. Very light with nutes just keep pH in check and top off water these days. Thanks

Looks like a calcium deficiency,but you have a good amount of tip burning too.My guess is you have a higher concentration of nutrients in that res then you think,ppm meters seem important for hydro,while I dont grow in dwc it would seem like youd want to monitor the nutrient concentration in the res?

Try taking your ph up to 6.0. It looks like you have low end lockout.

I know I know, everyone has a different requirement and they will argue to the death to defend the crown their own, but try it and see if the lock out clears up.

Drain your nutes and run straight water for 24 to 48 hours ph'ed at 6.0. Then start adding your nutes back to the system maintaining the 6.0.

This is the only strain doing this, here's another pic the issue is with a white widow x ak

Top leaves from problem plant

Bottom leaves from a different strain in same bucket. The other strain is mystery but it never has issues and grows out of control I end up chopping it to just a few branches and it outgrows it's space at an annoying rate.

Dumped most of the res and now at 6.1 with 750 ppm I'll check it later before I adjust pH. Tap has 230

Just the white x ak strain I'm having an issue with

Strains vary a good bit so makes sense its only the one strain. I agree with lowering the ppm, possibly cal/mag problem by the brown spots, i had cal/mag problem last grow and was in line with a high ppm for the specific strain. Cal/mag uptake happens at a higher ph so the higher ph suggestion is on point as well. 3squared is way more experienced than me so I vote follow his advice that I agree with thru my experience as well.

Looks like a Calmag issue. Rust spots is a sign of low calcium and magnesium. Not having it,or not checking ppms is like plant suicide in my opinion when running hydro. I've been using the same nutrient line for a while and I'm pretty sure what I add almost what the ppms are going to be, but assuming and knowing are two different things. I'd bump up you Calmag and use a ppm meter. Better to know how much nutes you have in there rather than guessing. You also stated same bucket! That's another BIG MISTAKE. Different strains will demand different nutrients uptakes, while one plant maybe thriving the other will be starving. It's really hard to keep a good balance when growing two different strains in the same pot even when they're the same strain. Just my 2 cents

Smoke1