Brown rusty spots on all leaves

Hello,

This is my first attempt to grow. The plants are 5 of the PPP Nirvana strain and 5 of the Nirvana "surprise" seeds.

The PPP strain seems to be very resilient.
One of the "surprise" plants, however, is showing all the symptoms of any impropriety very fast, sooner than others. I attached pictures of that plant. Please advise what can it be and how would you suggest to address it.

First, the plants are in 6"x 6" rockwool cubes, hydro. I had them under 8 of T5 lights for a little over a month (while I was working on my veg room). 230+ par reading on the canopy. I used to dip them in to the feeding solution (Flora by General Hydroponics, equal amounts of Flora Micro, Gro, and Flower + a little CaMag+ totaling 900-950 PPM in RO water, 7 ppm initially, 5.6-5.9 PH).
Two days ago I moved them into the veg room under a LEC 630 W, CMH, onto the beautiful ebb and flow table. Dipped them in the feeding solution one last time and put onto the table.
One day later I had enough RO water in the E&F reservoir and finally yesterday I was able to run the feeding system. I mixed the nutrients in the reservoir, but was concerned that they haven't mixed well to show a correct PPM. I fed them yesterday with 650+PPM feeding solution. I mixed this time 2 parts of Micro, 3 parts of Gro, 1 part of Flower, 1 part of CaMag+. PH 5.7.

Today the "indicator" plant shows brown, rusty spots. Some of the plants too got some of the leaves showing those spots but not as much as this one on the picture. Note the very tips of the serrated leaves are brown.

I read similar threads and people say - nutrient lockout, burn, need to flush, etc.
Then, calcium deficiency, some say.
Maybe I underfed them? Or overfed? Maybe my proportions of feeding components are wrong?
I am trying to figure it out and absolutely failing at that. Please help if you have any definitive answer to this problem.

Thank you!

Double check the ph...use a second device or paper...

Calcium Def. Up the calmag and make sure ph is correct.

http://www.growweedeasy.com/calcium-deficiency-cannabis

Also, those spots won't go away. Keep an eye on new growth for improvements. good luck

kind of unlikely to be a calmag problem since the trio has cal and mag and the OP says they are giving some extra.
hard to say what the problem is. could this be a heat problem? if not maybe a nutrient is missing? I was never impressed by the trio by GH because it always seems like something was missing. You have to learn what plants need check that with the contents of the bottles and see if everything is there. If not, maybe GH has another product you're suppose to buy. pays to do your research.
you might compare your feeding with GH schedules if you haven't already.
https://www.google.com/search?q=gh+feeding+charts&biw=1024&bih=618&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjxxOa2n_bQAhVnrlQKHRorBBUQsAQIHw#imgdii=UXeKR6BY_ryE1M:;UXeKR6BY_ryE1M:;7mTR8srUgu12rM:&imgrc=UXeKR6BY_ryE1M:

It's calcium deficiency. Probably from improper ph, not the nutes.

what is the correct pH range for a hydro grow?

OK @Meridith. You are using RO water. You need to make sure that you add back enough calcium and magnesium. @polishpollack, You're right there is something else going on as his Ph should be ok...The new growth looks like Nitrogen burn with the tips of the leaves being burned. They also look a little overwatered to me. I'm not sure 100% on all symptoms, but the rust spots are from lack of calcium. Good luck though.

Thank you everyone.
Here is what I found:
The symptoms of calcium def and magnesium def look quite similar. I found images of calcium deficiency and they looked similar but not exactly like mine. Yet again, people who claimed their plants had calcium def could have been as novice as I am. I believe that what I have here is magnesium deficiency advanced stage (see the attached image from Jorge Cervantes).
Earlier I also posted on the forum that the leaves of my plants had light yellowish spots which could have been either magnesium or manganese def. I believe back then my leaves had the same as on pictures A and C and now it is a D. Yet, my plant leaves also seem awfully similar to potassium deficiency (attached) stage D.

I also looked into the ph problem because I found that high ph prevents root from absorbing nutrients. The feeding solution ph is correct.
I then poured 2.5 gallons of clean RO water, adjusted its ph to 5.6 and dunked the rockwool cube of the affected plant into this water several times. Then I let water drain from under the plastic film by tilting the cube on one side and another. Afterwards I measured the PH. It was 7.3.
So, regardless of my feeding solution PH the PH of the growing medium was very high.
I read that people say that algae that grows on the cubes is not harming the plants. My guess (just a guess) that it alters the PH. It is a theory.
The PPM after one wash went up about 20-30. I adjusted the PH to 5.6 and dunked the cube again and again. The final PPM was about 150.
I did this all in a loop until the runoff from the cube was about 5.7 PH.
Then I dunked the cube into the feeding solution with 5.6 PH, let it drain one final time and mounted onto its place.
I didn't want top leave the plant without the feeding solution because I believe that drastic changes shock the plants. So while I took care of the PH issue in the medium, I wanted my plants to have enough food when they need. Besides, my feeding solution is just a basic solution + CaMag

I am now going over all of my plants and going to flush them. I am now impatiently waiting for the RO water to fill the buckets, then boil a kettle of water to adjust the water temp, PH and give it a go.
Then, since I concluded (I think correctly) that it is not calcium def but manganese, I will do foliar spray with epsom salt. Perhaps tomorrow or later today.
I will update this post because I think there are many newbies like me who go through the same or similar issues. I will update with the results.

Rock wool needs to be buffered down
It's naturally pH high

High pH locked out micros...like calcium.
Far from a noob. Just trying to help. Good luck.

Thank you so very much for your responses. I felt like drowning. This forum is like a safety net....
@Antman15 Thank you for the ideas. Yes, I can see clearly that the brown tips are very much look like nutrient burn. Then, combined with the spots (provided that those people who posted pictures of calcium def really did have calcium deficiency) they look very much similar.
My confusion here is that if my plants could not feed due to the high PH in the medium itself, then how could they get nutrient burn?
Does PH affect only the micro element consumption and not the NPK?

You are also right, they seem overwatered. The leaves droop.
I had an impression that E&F is hard to overwater just because the medium itself supposed to be porous and hold oxygen.
I only watered once a day and not even every day.

Thank you again.

Thank you for all who responded.

Antman15 said:

Calcium Def. Up the calmag and make sure ph is correct.

http://www.growweedeasy.com/calcium-deficiency-cannabis

Click to expand...

bullSnot said:

Double check the ph...use a second device or paper...

Click to expand...

Double whammy. Ph looks off, and leaves look a bit starved

I'm dizzy from reading all of this.

Meredith, why are you dunking the rockwool? This is the first I've ever heard of doing this and I've been reading these forums for years. Don't your roots grow outside of the rockwool and isn't this more important ppm and pH-wise than what your pH is of rockwool runoff? At this point, I'd like to say I think you were 99% right when you thought that the yellow spotting was magnesium def. That's how it starts. I've seen calcium def start as orange spotting which will turn brown when that area of leaf tissue dies. It could be something else, but one thing is certain, yellow spotting is not calcium. Antman's insistence on calcium is too much. I didn't want to say anything and I'm so glad that you were able to get closer to figuring this out on your own, with Jorge's help. The remaining 1% is for the possibility that it's another nutrient, but I've seen early mag def and it really looks like a golden-yellow spot at first. Epsom is magnesium sulfate, if I remember right, and small amounts per gallon, like one half teaspoon will probably make all the difference in a couple of days. The weird thing is you're using fert that has calmag in it and you are giving more. I never saw where you posted the yellow color was taking place. Was this done in a different thread?
Maybe all the dunking is common in ebb and flow. I wouldn't know cuz I'm a dwc kind of person, which I highly recommend by the way. I just don't see how all the dunking and rinsing will help. DWC doesn't rinse anything, you set it and check it morning and night, and that's about it. Fighting with pH can make things worse for you cuz you end up always second-guessing yourself. Focus on the best ppm first, then be concerned with pH cuz it's ppm that drives pH, not the other way around.
Listen to Jorge more too.

Plants uptake nutrients at different pH levels you can lock out calcium but still uptake nitrogen with high pH. That is why you can have the burned Leaf tips and still have Calcium deficiency

Even good old Jorge uses a pH level chart for nutrient uptake

See attached file

As far as the overwatering. That is actually lack of O2 so you can "overwater" with any media if there isn't enough oxygen in the water. Make sure that you are aerating your reservoir water.

Wow, OP, maybe you overcomplicated shit for your first grow? Maybe some decent soil and fucking tap water would have been a better way to start? I think people tend to overthink this stuff. You can grow fire with a $20 bag of dirt (usually need to add a grip of perlite) and some Jack's 20-20-20, and in that case there's often no need to feed until the last 45-60 days. I bet your tap water is fine, too, if it is under 200ppm and anywhere near 7.0 pH you should try it. RO is great and all, but Cannabis is just a regular-old plant, no magic to it, just grows like a weed, and the more complexity one adds the more shit can go wrong. That's my soapbox speech for the day.

As for the problem at hand @Antman15 is very likely correct, high pH causing calcium deficiency is my overriding opinion as well. I know you are using rockwool, but not sure you prepped it correctly. I soak my rockwool, when I use it, in pH 4.5-5.5 water for about a day then rinse it with a light 200-300ppm nute solution, somewhere between 5.5-6.0. I only really use it for cloning, and I am not even doing that right now, I went simpler.

*K.I.S.S.*