First DWC. Just switched to 12hr w/ new res. Issue in 24hr

Hi everyone. I've just entered flowering with my first DWC. Yesterday (last night@430) I changed out the buckets cleaned rinsed and refilled with fresh grow nutrients for the first half of transitioning. Using Dutch Nutrient Formula. I know others that run the same program but under different methods so I feel confident saying the nutrients are not the issue,by themselves, perhaps I've done something. I upped the strength from 600ppm to 900. pH is 5.7. the system I have is just basic. I had three buckets so that's what I'm using. 3 5 gallon buckets with 6" netpots/hydrotron . The system is being Fed by a vivosun 32watt 60l/min air pump feeding into two 1.5"x4" air stones per bucket. The environment is probably running on the cool side but I don't have to use AC or heating for the first time in ages so I'm trying to enjoy it. Environment is 28°c & 52%RH. I threw a exhale 365 in this tent a few months back so it should be kicking into its full potential for what that's worth. The light is a growflux 600tl running the bloom starting spectrum. I think it's called something else but you get the idea. So the problem is that after the changes last night I came to check up on my girls and one is showing signs of either toxicity or deficiency. The leaves are showing some brown or copper looking sections on some leaves and the general texture of the plant itself feels different than what it did just yesterday. I've attached a few pictures if someone could please give me some suggestions as to how to repair the damage I've caused I'd be very grateful. Cheers

nute burn for sure.
roots ok?
pH you sure is 5.7?
900ppm too much for DWC in my opinion
nute lockout?
ppms dropping? rising? same?

I can't believe the luck. I went back when lights came back on and the PH meter is done. Can't think of a reason it wouldn't be working. No water damage, hasn't been dropped or anything like that. Changed the batteries just incase. Just reads 0000. Ordered a new one from Amazon but the quickest delivery is late Wednesday. Gotta say I'm a little worried. Do I have any safe options for how to move forward over the next few days? As for what to do if it makes it thru to Wednesday. I had read that the ppm should be increased weekly until the final concentration of 1200 to 1500 was met by the beginning of week 6. The feeding instructions from the nutrient manufacturers state that ppm should be increased to a final concentration of 2000 ppm. I know they always say to feed to much but from the few things I read and reduction of around a third I thought I was on track. what is everyone else finding is the right ppm at different change out times? I would take any good advice on any aspect of how to be successful at this. I have also recently read that dwc like aggressive pruning? Other than the lower branches and bud sites I don't normally prune too much. The recommended pruning suggested to me is almost like that swazzie(?) Again thanks for any advice and help. I greatly appreciate it

Well now you know, PH meters can't be trusted and the old fashioned PH drops will get you close enough. Most people never check the calibration of their ppm meter and many don't do the math so most people speak in EC around here. I have a feeling if you tested your ppm meter you will see that your nutes are stronger than you think they are. I almost never prune anything unless they are really bushy bitches.

It's funny you say that. I just calibrated the ppm meter when I received the PH meter as it was a 3 in 1, EC,ppm,temp. So when I did the initial calibration of the new meters EC I did my original ppm meter. It was off but not nearly as much as it probably should have been since it is almost 3 years old

Realbax said:

I had read that the ppm should be increased weekly until the final concentration of 1200 to 1500 was met by the beginning of week 6. The feeding instructions from the nutrient manufacturers state that ppm should be increased to a final concentration of 2000 ppm.

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you shouldn't need to go over 1.2 EC (600ppm)

Although I disagree with how high you can go, I used Lucas in DWC which is 1200, I think 99% of growers can agree that 2000 is insane.

I run 500-800 ppm (500scale) in veg and
1000-1200 in bloom.

DaFreak said:

Although I disagree with how high you can go, I used Lucas in DWC which is 1200, I think 99% of growers can agree that 2000 is insane.

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Depends on how you run your buckets. With no res swap, it's easy to hit 1000ppm in veg.