please tell me this problem

I have my plants in a flo n gro cap flood system. I flood every 4 hours in hydroton with RO water and GH maxibloom at little under 1 tsp/gal with some additives. The only plants getting affected are the ones directly under the light. The plants on the edges of light are nice green with no problems but under the light the leaves are yellowing/brown blotching which I thought of as P def? The plants are close to light and do have a slight light nurn but no heat burn. now that I'm looking at some leaves maybe Cal def? I have no calmag in RO water

Rh is 45-55
temps about 75

What part of the plant is yellowing? Are they the biggest fans? Also how much ppm or ec are u feeding?

westcoast420 said:

What part of the plant is yellowing? Are they the biggest fans? Also how much ppm or ec are u feeding?

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The middle and lowers. The tops are fine. I start out at around 1.1 ec and ph 5.7-5.9. Just check ph and its 6.3 and e.c shows 3.0 right now lol. I never understand the e.c

larrypizzimp93 said:

The middle and lowers. The tops are fine. I start out at around 1.1 ec and ph 5.7-5.9. Just check ph and its 6.3 and e.c shows 3.0 right now lol. I never understand the e.c

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Could be as simple as those plants have a higher metabolism because they're getting more light.

Could be light stress. What type of lights are you using and how close.
If the top leaves are folding in, like a canoe then its more than likely light stress. Symptoms seem the same when I dealt with it.

Is this your first run with Maxibloom? I tried some Maxibloom last run because everyone said how easy it is. I was using less than 1 tsp/gal. I started getting yellow leaves and didn't have time to try and figure it out so I went back to Floranova. They turned around with Floranova.

They look about done, just fading out.

70's natureboy said:

Is this your first run with Maxibloom? I tried some Maxibloom last run because everyone said how easy it is. I was using less than 1 tsp/gal. I started getting yellow leaves and didn't have time to try and figure it out so I went back to Floranova. They turned around with Floranova.

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I'm kinda new with it only have a few harvests with it. I had a lot better results with the 3 part fox farm. I'm up to a tsp/gal now since that's supposed to be lucas formula. I think i'm gonna switch to the 3 part GH flora. maxi leaves a lot of salt behind in res

Jypsy Dog said:

They look about done, just fading out.

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They're about week 4-5 right now. hairs just starting to orange

Sure looks like a phosphorous deficiency. Whats your feed PPM and pH? What medium in in the system? Flood frequency?

Renfro said:

Sure looks like a phosphorous deficiency. Whats your feed PPM and pH? What medium in in the system? Flood frequency?

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I have liquid koolbloom in it at 2ml/gal. Hydroton and flooding every 4 hours. Just changed water last night. was at 1050ppm on .5 scale and it went down to 1000. ph went from 5.6-6.0. should I raise it about 100ppm?

The problem you are definitely having is that you are not supplementing your RO water with Cal-Mag.

Do a google search on Magnesium deficiency as well as Calcium deficiency. At the same time google the importance of magnesium while growing as well as the importance of calcium while growing.

digging said:

The problem you are definitely having is that you are not supplementing your RO water with Cal-Mag.

Do a google search on Magnesium deficiency as well as Calcium deficiency. At the same time google the importance of magnesium while growing as well as the importance of calcium while growing.

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I was thinking possibility but I read maxibloom should have enough in it

Ca is immobile. His top leaves would be shitty. Don't know about maxibloom but I read you were giving it pk also.
I say nitrogen and probably normal because your near the end and it is sucking it out of the plant. See if leaves like that pop right off when you tug them. But hey, I may be dead wrong.

No Calmag, in RO water. Yep that's an issue. I treat those 2 like a primary nutrients. I use 4ml/gal. Cannabis is a calcium /magnesium whore.

5BY5LEC said:

Ca is immobile. His top leaves would be shitty. Don't know about maxibloom but I read you were giving it pk also.
I say nitrogen and probably normal because your near the end and it is sucking it out of the plant. See if leaves like that pop right off when you tug them. But hey, I may be dead wrong.

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Mmost web sites say top leaves affected with Ca Def.but all Ive seen IME is middle leaves or older ones.Never have I seen new leaves have spots first.

Huh. I always see it at the top. Spots and shit.
Either way he has went his whole grow without it, and has done fine. If he really needed calmag it would have shown up before this point, don't you guys think?

if it's just some of the lowers, if they aren't receiving good light, sometimes they just yellow up and die.

i don't see any evidence of cal or mg deficiency in the pic of the 2 leaves.

It could also be too much phosphorous. They look very similar. With the koolbloom I don't see it being low on phosphorous. Did this start after adding the koolbloom into the mix?

Renfro said:

It could also be too much phosphorous. They look very similar. With the koolbloom I don't see it being low on phosphorous. Did this start after adding the koolbloom into the mix?

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Too much P will lock out N quickly. Dyna Gro Bloom (3-12-6) did it to me in a few days. Luckily I caught it in time.