Thinking Phosphorus? Hydro

So I’m hoping you cannabis growing gurus can give me a hand there cause I’m not sure what the problem is, and it’s not getting better

plants are in hydro. It’s sort of a hybrid RDWC/ undercurrent. Plants are set into a poly top in a flood table with solution just circulated below into a large res. Total volume ~120 litres. They are drinking about 5 litres a day with the PPM also dropping

nutes are from a local greenhouse supply. 3-11-27 with added calcium nitrate and Epsom salts. Using 3-2-1 ratio. Basically Jacks formula

res stays close to 750ppm @500scale, or 1.5EC. at close to 6.0PH. I calibrate both BlueLab pens weekly

Temps are 78 lights on and 69 lights off
RH average is 51% with high of 55% and a low of 47%. I know the VPD is off but if I get higher humidity I get PM almost on que

light is a 600w LED custom 3000k with bridgelux GEN2 strips. Love the thing

so anyways about the plants. I’m thinking phosphorus deficiency with the purple stems. But the odd tip drop at the end of the leaves throws me off, I don’t think it’s Nitrogen toxicity as the plants aren’t that dark at all. It is working from the bottom up for sure. And the newest growth doesn’t look bad at all.

anyone got any ideas. I just did a res change this evening

def not a nitrogen toxicity, looks more like a Potassium deficiency or an infestation.
are you adding cal/mag to your res?

Jpwt92 said:

def not a nitrogen toxicity, looks more like a Potassium deficiency or an infestation.
are you adding cal/mag to your res?

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Not an infestation just checked for bugs.

yes I am basically runnings jacks 3-2-1 so calcium nitrate and magnesium(Epsom salts)

I can up my PPM a bit maybe 800?

Anyone else have any ideas?

What do the roots look like? What kind of EC pen you running because the ph looks off

What type of water are you using?

onegreenthumb said:

What do the roots look like? What kind of EC pen you running because the ph looks off

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roots are white, I run Sterile res with pool shock as well. I don’t think it’s that as they are still drinking more and more water daily as they grow. Eating as well

I use a blue lab ph pen and I calibrate it weekly. I did check it back against a 9,7 and 4 solution to make sure it is reading properly

Mirrordawn said:

What type of water are you using?

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RO water

I would up the PPM but only using the base, no more cal nitrate and no more epsom. Get up around 1000 PPM.

Renfro said:

I would up the PPM but only using the base, no more cal nitrate and no more epsom. Get up around 1000 PPM.

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I’ll give it a shot. To be honest thinking about it I never checked the PPm of the cal nitrate and Epsom salts before adding the base.
Do you think I could have to much Mag cussing lockout of calcium and potassium? It looks like they are deficient in both. Maybe my ratio is off

I’ll up the PPM and give it some time

ToFarGone said:

roots are white, I run Sterile res with pool shock as well. I don’t think it’s that as they are still drinking more and more water daily as they grow. Eating as well

I use a blue lab ph pen and I calibrate it weekly. I did check it back against a 9,7 and 4 solution to make sure it is reading properly

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Are you aerating the res? Wow I didn't know people used pool shock in the res, I had a hard time with DWC when I tried it ...I can see something is going on, but I am of no help I hope you tell us when you get it sorted I want to know what it is

onegreenthumb said:

Are you aerating the res? Wow I didn't know people used pool shock in the res, I had a hard time with DWC when I tried it ...I can see something is going on, but I am of no help I hope you tell us when you get it sorted I want to know what it is

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Yeah the res is aerated through a waterfall back to the res underneath the flood table

Have you tried to use an air stone yet? I run hempy if I aerate my water I get better results and folks on here tell me I dont need to aerate, but my plants are a lot more healthy if I do

ToFarGone said:

I’ll give it a shot. To be honest thinking about it I never checked the PPm of the cal nitrate and Epsom salts before adding the base.
Do you think I could have to much Mag cussing lockout of calcium and potassium? It looks like they are deficient in both. Maybe my ratio is off

I’ll up the PPM and give it some time

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You could try running the numbers with my calculator. It's made so you can add products pretty easy using the label percentages. Already has a Cal Nitrate and Mag sulfate.

Renfro said:

You could try running the numbers with my calculator. It's made so you can add products pretty easy using the label percentages. Already has a Cal Nitrate and Mag sulfate.

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I will look into this when I get home tonight

what ppm for the CaL nitrate and mag should I be aiming for? Or is it a ratio between the three?

Alright so I have had my ppm around 1100ppm and it seems like it’s getting worse and still moving up the plants. Starting to affect the newest growth. I am going to Chnage the res this evening. Any suggestions on what ratios and how much to add/ ppm to shoot for of each. I have

3-11-27 hydro nutes
15-0-0-26 calcium nitrate
And Epsom salts

@Renfro any ideas?

Renfro said:

You could try running the numbers with my calculator. It's made so you can add products pretty easy using the label percentages. Already has a Cal Nitrate and Mag sulfate.

Click to expand...

i also looked into this calculator. how come the "liters" page has all whacked numbers?

ToFarGone said:

Alright so I have had my ppm around 1100ppm and it seems like it’s getting worse and still moving up the plants. Starting to affect the newest growth. I am going to Chnage the res this evening. Any suggestions on what ratios and how much to add/ ppm to shoot for of each. I have

3-11-27 hydro nutes
15-0-0-26 calcium nitrate
And Epsom salts

@Renfro any ideas?

Click to expand...

stop using the 15-0-0-26 calcium nitrate,
go to about 650 of the 3/11/27 and add about a 100ppms of epsom salt, add 2ml per gal of cal/mag, keep water temp about 72 and ph at 6.0-6.2 check ph daily ....get some ph drops to check every now and again or when you have a ph swing to make sure the pen is accurate and before you add ph up or down when there is a big swing so you dont add ph up down when you dont need to if your pen went whacko on you.
pick off all the jacked up leaves.

yes the mag and cal mag are about the same thing along with the calcium nitrate but the cal/mag has less nitrogen in it. and or if the 15-0-0-26 calcium nitrate is actually 15/0/26 then I would guess that your adding more K than need be.

Bernie420 said:

stop using the 15-0-0-26 calcium nitrate,
go to about 650 of the 3/11/27 and add about a 100ppms of epsom salt, add 2ml per gal of cal/mag, keep water temp about 72 and ph at 6.0-6.2 check ph daily ....get some ph drops to check every now and again or when you have a ph swing to make sure the pen is accurate and before you add ph up or down when there is a big swing so you dont add ph up down when you dont need to if your pen went whacko on you.
pick off all the jacked up leaves.

yes the mag and cal mag are about the same thing along with the calcium nitrate but the cal/mag has less nitrogen in it. and or if the 15-0-0-26 calcium nitrate is actually 15/0/26 then I would guess that your adding more K than need be.

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I can tell you there is no K in the calcium nitrate. But I will go grab some proper calmag I suppose. was really hoping to keep using my calcium nitrate

ToFarGone said:

I can tell you there is no K in the calcium nitrate. But I will go grab some proper calmag I suppose. was really hoping to keep using my calcium nitrate

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Yeah i dont what it is my bag of is downstairs, you keep forgetting thats why you have to keep learning.

You dont need that much nitrogen in flower or use it but know that you want to give it way less nitrogen in flower compared to veg.

Then you dont have to buy anything. I just use the 2ml per gal and make it easy on myself the cal/mag has less nitrogen i dont know if it cheaper doing it another way but its easier this way for me.