Leave problems (pics). Help with diagnosis

Please help. Most of my plants seem to be having the same problem to some degree. The one that has it the worst is clearly dying. I want to fix it before I lose them all. Leaves are turning yellow/brown in spots and curling upward. I believed it to be a magnesium defeicency, so I gave the worst ones epsom salt two days ago, but have seen the problem advance at the same rate.

Northern lights
600w light
75-84 degrees
RH very low at 16%
RO water + Lucas formula
all around 900ppm
5.8-6.3ph
3 tetra whisper 100 air pumps powering 2 buckets each

Any thoughts on whats wrong with my plants? (Please look at the 3rd & 4th pic for leave problem)

How old are they? RH should be around 60%! Also if they are young maybe cut down on the nukes a bite. It doent look like they are not getting enough of something, they look like they are getting to much. If I were you I would start by just doing a flush with just water for a few days and see if that helps at all. I think its a combo of the room being a little warm and die and then your ppm is a little high. PH seems good. RO water is the best. Is your light air cooled and how far from the plants is it?

I ment room being dry not die. lol my bad

it looks like nutrition burn to me... especially the picture of the burnt leaf.. try giving your plants just balanced water for a few days. i dont know much about hydro set-ups but to soil growers i would leach your plants . this means to get at least a litre of water draining out the bottom to rid excess nutrition ..
peace

Thanks for the quick replys, Ill go ahead and give them just straight RO water for a few days.

The light is air cooled by a 6"inch 406cfm Sunleaves Windtunnel. Light is 20" inches away.

They are 20 days old. I bought a cheap humidifier and got what Id paid for. Any humidifier recommendations?

Its going to take some serious work and a bit of luck to get these back to health. They're pretty much fried. The necrosis in those upper leaves has already set in, so it's only a matter of time, couple weeks maybe. Only the newest of growth is undamaged right now.

This is purely a ph problem, if it was simply over nuting, you wouldn't have that light green color throughout. If you ph is good and you're overdosing them on nutes, the color is generally dark green with the brown spotting(in veg), since you're feeding them a fair amount of nitrogen.

Well I already put a couple that are in the early stages in pure RO water. I'll probably pull the badly effected one.

I generally keep the PH around 5.8-6.3. I don't try to fool with it too much.

They are all pretty light green, so I've considered that maybe it was too little nitrogen. Everyone says Lucas formula has plenty of N though.

It sucks not knowing.

What should I do from here?

looks more like a Calcium deficiency to me... I'd try some GO Cal-mg

Punk said:

Its going to take some serious work and a bit of luck to get these back to health. They're pretty much fried. The necrosis in those upper leaves has already set in, so it's only a matter of time, couple weeks maybe. Only the newest of growth is undamaged right now.

This is purely a ph problem, if it was simply over nuting, you wouldn't have that light green color throughout. If you ph is good and you're overdosing them on nutes, the color is generally dark green with the brown spotting(in veg), since you're feeding them a fair amount of nitrogen.

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Hey punk! Not tryn to be rude but just wondering what makes you think its PH problem if his ph have been 5.8-6.3? I understand sometimes the ph in the water does not read the true ph of the medium but with these plants being so young that shouldnt be the problem right? Again not tryn 2 be an ass just like to know what makes you think that. Im always learning and any info on any subject about growing if worth learning!

All I know is the problem is advancing. I killed one, and its looking like i'll have to kill one or two more most likely. I have 3 healthy ones that don't have the problem all that bad...yet.

I feel like I'm gonna lose them all, and I don't understand why.

I had one other grow years ago. My conditions weren't nearly as perfect...3 plants, different strains in one 5 gallon tub. Only drop ph kit. Lucas forumla. 88degree temps. Had no problems. Yeilded like 7 or 8 0z wet under one 400w. WTF.

Well i agree with punk that they may have been past the point of no return. Have you been using fresh water? Also take a spray bottle and stay every few hours to raise the RH. Also a wet towl in front of your fan will also raise it.

Flushed the unhealthy ones with pure RO water for 3 days:
Just gave them all buckets Fresh RO
0-8-16- Lucas + 2.5mg per gallon of Botanicare Cal-Mag plus (good dose?)
PPM 1000
PH 5.8

I killed the badly effected one, and the next bad looking one hasn't gotten any worse. Hopefully its all good from here on.

The NL will be 4 weeks old from seed on the 9th and I may flip to 12/12 then. Thoughts on that + cloning/topping?

Btw the two soil plants in the middle are WW clones in soil.

Scrogreen: The wet towel worked great! Raised my RH from a consistent 16% to 25-30 as long as I re-wet it once or twice a day. Plants seemed a bit perked up right away.

dimajna said:

Flushed the unhealthy ones with pure RO water for 3 days:
Just gave them all buckets Fresh RO
0-8-16- Lucas + 2.5mg per gallon of Botanicare Cal-Mag plus (good dose?)
PPM 1000
PH 5.8

I killed the badly effected one, and the next bad looking one hasn't gotten any worse. Hopefully its all good from here on.

The NL will be 4 weeks old from seed on the 9th and I may flip to 12/12 then. Thoughts on that + cloning/topping?

Btw the two soil plants in the middle are WW clones in soil.

Scrogreen: The wet towel worked great! Raised my RH from a consistent 16% to 25-30 as long as I re-wet it once or twice a day. Plants seemed a bit perked up right away.

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NICE BRO!!!! Glad to hear thats helping but you really need to get it higher because of how young they are. 60% would be perfect. I love WW!!! Thats what I got going now, so good!! 1000ppm seems good. I wouldnt go much higher for a week or 2. Let them recover. PH is perfect. I havent used Cal-Mag b4 so not sure if thats a good dose or not but if you just follow whats on the package you will be fine. Also forgot to ask you about your fan size? How big is your room and how big is your fan? If your fan is to big for your room that is one reason why your RH is so low. I have a fan that was to big for my tent and it caused all kinds of problems. Now I have the fan on a timer to turn on for 1:30 every 5 mins. Your fan should change the air in your room once every 5 mins. If your good at math you can figure this out if not there are a few web sites with this info. But again you reallt need that RH up. Once they get a better root base it wont hurt them so bad but the first few weeks and the last few weeks you must be right on. Still glad to hear things are going better!!! We shall get your room perfect!!!!