Runoff PPM

In coco/perlite. 4 plants, 2 on left side of tent have issues. First one is classic mag symptoms, whether it’s from a lack of mag or excess of calcium, yet to be determined. Second plant looks like mag too but then a few small dots on bigger but not biggest leaves getting light, indicating calcium. Feeding 2-3 x a day @ 700 ppm roughly or 1.4 EC. All fed from same Rez. Except the last 2 days I’ve given the 2 sickly plants extra calmag, 125 ppm starting water brought it up to 450ish ppm then added canna A&B to bring up to 700-750 ish PPm (1.4-1.5 EC) My question is this: if I pour a half gallon of distilled through and the runoff of this is 435 ppm...is it safe to assume my coco is has been stealing all the extra cal & mag I’ve been giving it? If that was the case it wouldn’t show up in the runoff since it won’t be able to be washed out, correct? In cocodelphia, it’s pre buffered & had zero issues last run w/ it, always bringing ppm of tap water to 200 b4 adding nutes, worked like I charm except this time, I left it in the breezeway though in between runs so maybe I didn’t store it properly? And unbuffered it’s self?
 
Does that make sense though? If I feed @ 700 ppm daily & pour 0 ppm water into media, only enough until runoff (half gallon maybe) & the runoff is in the 400’s, the plant is lighter green than the rest so I can’t imagine it’s sucked up 300 ppm of NPK? Isnt it more plausible the coco is stealing all my cal mag? And because of this is just not making it into the runoff? And that’s why the low reading? Because it’s holding onto it?
 
I feed w/ every water I just wanted to get a grip on my ppms so I can have better understanding if it’s a toxicity or deficiency, but if runoff so low and I feed @ 700 and I question how I stored my prebufferwd coco now I’m thinking it’s just stealing all the calmag and should toss the pbout to go to flower I need to either fix it or remove plant from tent in next couple days.
 
I was going to foliar epsoms but the small spots suggest calcium too though, no? And about to go to flower I don’t think I can foliar epsoms the entire time, if indeed the coco is stealing it all. I already bring tap from 125 to 200 ppm w/ calimagic
 

TintEastwood

Well-Known Member
Not familiar with the AB nutes.
The ratios can matter.

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Being coco, I run the Ca Mg a touch high in veg thru stretch. I'm using cmh.

Have chased my tail many times with coco woes. Including excess K.
 
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Attikus112

Well-Known Member
I was going to foliar epsoms but the small spots suggest calcium too though, no? And about to go to flower I don’t think I can foliar epsoms the entire time, if indeed the coco is stealing it all. I already bring tap from 125 to 200 ppm w/ calimagic
I believe unbuffered coco typically has the cation exchange sites filled with sodium and potassium but those get bumped off by magnesium and calcium. Once those sites are filled your coco shouldn't keep stealing the Ca and Mg from your nutrient solution. As the coco breaks down more sites will get exposed but I don't think that has a significant effect on feeding. So if your issue is due to unbuffered coco i would expect the coco to buffer with time from feeding and they foliar feed should be a temporary measure to improve the health of the plant.

I may have missed it somewhere, but whats the pH of your nutrient solution?

One final thought, your bringing your base water up to 200ppm from 125ppm. That's not a huge bump from calimagic and without knowing what contributes to the 125ppm your base water might still be low on Ca or Mg.
 
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I believe unbuffered coco typically has the cation exchange sites filled with sodium and potassium but those get bumped off by magnesium and calcium. Once those sites are filled your coco shouldn't keep stealing the Ca and Mg from your nutrient solution. As the coco breaks down more sites will get exposed but I don't think that has a significant effect on feeding. So if your issue is due to unbuffered coco i would expect the coco to buffer with time from feeding and they foliar feed should be a temporary measure to improve the health of the plant.

I may have missed it somewhere, but whats the pH of your nutrient solution?

One final thought, your bringing your base water up to 200ppm from 125ppm. That's not a huge bump from calimagic and without knowing what contributes to the 125ppm your base water might still be low on Ca or Mg.
Didn’t miss it just scatter brained. 5.7-5.8 and let rise to a max of 6.3.
That’s what I thought too, it should be being buffered especially w/ giving it extra 400 ppm of calmag last couple days, plus 300 more of base mix. Now I’m thinking I’m giving too much calcium? You? I doubt I’m giving too much K the plants not that dark green & canna has low K to account for the coco. My tap last run was 150 though, and brought it up to 200 w/ calimagic, perfect run. This time it’s 125, I’m still bringing it to 200 w/ calmag so It is getting wxtra calcium just from that aspect id assume, although I don’t know which elements consist of the 25 ppm difference in my tap. last run I also multiplied the entire canna schedule by 0.7. this run because they werent overly dark and not as burnt tips, I’m multiplying by 0.9 . So extra calcium, again. My EC is still around 1.4-1.5 though. I think I’m giving too much Ca now? I’d say not enough calmag but it’s a 25 ppm difference and their getting more calmag just from being fed the X 0.9 mix than the 0.7 ratios they were getting last run. I’d figure it’d be balanced out. Idk if should continue X’ ing by 0.9 and just stop adding the calmag to my starting tap water? Or add calmag to 200 and go back to X by 0.7 like I did last time? Or maybe I’m completely off and my tap has zero cal or mag? Although I do see that build up on my dogs water dish from time to time from cal so idfk lol I was always told to add additional calmag w/ coco so just confused now.
 
And I have a plant unaffected, biggest, most vigorous, maybe that’s the reason it’s unaffected? They’re fed the same mix so you think It can handle/demands a lil more calcium just by nature? If I was giving too little I would expect this most vigorous one to be the hardest hit?
 

Attikus112

Well-Known Member
Still might be worth an Epsom foliar or add some to your base nutrients. That will allow you to bump up the Mg without adding Ca.

Are you able to check the roots to verify you don't have any root rot? I know people say you can't over water coco but that hasn't been my experience.
 
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