100% RO water CalMag problem

Hey guys,

it´s my first grow using CalMag (I use Advanced Nutrients Sensi Cal Mag).

I´m on soil, day 25 of veg. My tap water has 1.3 EC, 218mg/L Ca and 43mg/L Mg.
I use 100% RO water and add around 50% of recommended dosage CalMag so I get around 0.3 EC.

Before, I used a multi mineral salt for fish aquarium. It worked nearly perfect in combination with 100% RO water on soil but has only 25mg/L Ca and 6mg/L Mg at 0.3EC.

Now at 0.3EC CalMag my plants show a Ca-deficiency.

Is it possible that it´s because I just go half of recommended dosage? But full dosage would be around 0.6EC-0.7. Another thing is, there is kelp in it which could be the reason of the EC?!

I just think 0.7EC for base water without nutrients is too high...

Does someone have experience with CalMag or 100% RO on soil?
I grow for around 5 years, I know how to water etc. so it has to be CalMag product problem.

Thanks a lot

Doesn't look like a calmag issue to me. Looks like a ph issue. Or lack of P.

3rd Monkey said:

Doesn't look like a calmag issue to me. Looks like a ph issue. Or lack of P.

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Before I thought it´s a pH issue. That´s why I measured my pH of my drain-> 6.4. I water with 6.5 so my pH is currently on point.
The smaller pot before (1.XL now 3L) I didn´t water till drain. Maybe my plants had problems before but not anymore..?!
I switched to my old product for aquarium last watering. Maybe I´ll give it one more try using only CalMag..?!

Thanks

Findus said:

Before I thought it´s a pH issue. That´s why I measured my pH of my drain-> 6.4. I water with 6.5 so my pH is currently on point.
The smaller pot before (1.XL now 3L) I didn´t water till drain. Maybe my plants had problems before but not anymore..?!
I switched to my old product for aquarium last watering. Maybe I´ll give it one more try using only CalMag..?!

Thanks

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Well with RO water, cal def is common. Since you gave it a low dose last time and your ph is on point, yea probably not enough calcium then.

Just out of curiosity though, what nutrients are you feeding it? Or what soil, if no nutes?

Upping calcium isn't going to hurt, just doesn't look like a "calcium only" thing to me.

Hey dude, thanks for replying!

3rd Monkey said:

Since you gave it a low dose

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Yes I was a bit nervous because of the EC and N... I heard that the kelp shows a bit random on the EC you know sth about that?
Is this normal Nitrogen or special Nitrogen in CalMag?
Product says: Calcium nitrate and magnesium nitrate.

3rd Monkey said:

what nutrients are you feeding it?

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I transplanted from 200ml pot -> 1,75L and now 3L pot with light mix from plagron which contains around 0,7-1,2EC.

Findus said:

Hey dude, thanks for replying!


Yes I was a bit nervous because of the EC and N... I heard that the kelp shows a bit random on the EC you know sth about that?
Is this normal Nitrogen or special Nitrogen in CalMag?
Product says: Calcium nitrate and magnesium nitrate.


I transplanted from 200ml pot -> 1,75L and now 3L pot with light mix from plagron which contains around 0,7-1,2EC.

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Kelp is good shit. I've used it as a dry amendment, so I can't speak of the EC, but I wouldn't worry about it harming them. They look plenty healthy to handle a dose of kelp and more calmag. The only thing you have to watch for is lockout if you give it too much, but just up it slowly.

Given the soil you are using, I would say you could likely push a full dose, but less is better until you work your way up.

3rd Monkey said:

Kelp is good shit. I've used it as a dry amendment, so I can't speak of the EC, but I wouldn't worry about it harming them. They look plenty healthy to handle a dose of kelp and more calmag. The only thing you have to watch for is lockout if you give it too much, but just up it slowly.

Given the soil you are using, I would say you could likely push a full dose, but less is better until you work your way up.

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Sounds like a solid answer you´ve given here. So you mean I should continue using RO and CalMag only and higher the dose, without my aquarium mineralizer that worked in the past? And that should work?
I´m from Germany and I think growers from US have much more experience with CalMag and RO.

But yea I´ll give 75% of the recommended dosage next I think.

Findus said:

Sounds like a solid answer you´ve given here. So you mean I should continue using RO and CalMag only and higher the dose, without my aquarium mineralizer that worked in the past? And that should work?
I´m from Germany and I think growers from US have much more experience with CalMag and RO.

But yea I´ll give 75% of the recommended dosage next I think.

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You can use either one you want. The plant won't care as long as it gets what it needs. If you like the aquarium salts, use those. If you want to use calmag, just up the dosage a little bit.

Some plants like more calcium than others so you have to feel them out and see how much each needs. The dosage on the bottle is a general guideline.

If the problem gets worse with a higher dose, flush with RO water and a half dose of calmag. If you don't water to runoff, you could have salts built up around the roots which is preventing nutes from going up.

Been to Germany before. Gorgeous country.

If your soil contains some (unbuffered) coco, the coco might be holding onto some of the calmag???

http://www.cannagardening.com/how_use_coco_coir_concept

It doesn´t cointain coco...

You'll be alright. Plants look great! Just dialing in is all.

What strain? It's got very good structure.

3rd Monkey said:

Plants look great!

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Thanks! AK47 from serious seeds. I bend them today, hope there will be many colas.
First time with nice cree leds. But I actually grow for 4 years...

Mate where you from?

Cheers

Findus said:

It doesn´t cointain coco...

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i see you are in germany. i would try to find general hydroponics floranova bloom. you can use it start to finish and when i used it with RO, i didnt' need calmag.

Findus said:

Thanks! AK47 from serious seeds. I bend them today, hope there will be many colas.
First time with nice cree leds. But I actually grow for 4 years...

Mate where you from?

Cheers

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I figured you've been growing for a while judging by the plants. Nutrients can be confusing with all the brands and different ratios with different ingredients. Have you ever tried organic?

East coast USA, Dutch heritage.

3rd Monkey said:

Have you ever tried organic?

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that's what i was thinking. if i was going to grow in dirt, i'd want to do soil that only needed water for the whole grow

rkymtnman said:

that's what i was thinking. if i was going to grow in dirt, i'd want to do soil that only needed water for the whole grow

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I only grow organic. I have a farm so the only thing I have to buy is coco lol. One day, I'll figure out how to grow a coconut tree here up north lol.

Side note, I do feed teas, so a little bit more than watering, but still easy.

rkymtnman said:

i would try to find general hydroponics floranova bloom

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My growshop has it in stock! But how do I use it? As a base water nutrient?
I just got a few grams left so I think for this round I´ll mix 0.2 EC or 100ppm aquarium remineralizer + 100ppm CalMag for my base. Test 1 plant with nova next run!

3rd Monkey said:

Have you ever tried organic?

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Last years were very stressfull had "no time" to read into this topic... But definitely will switch to organic asap!!!!

3rd Monkey said:

East coast USA, Dutch heritage.

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Been to USA and felt in love.

Cheers

Findus said:

My growshop has it in stock! But how do I use it? As a base water nutrient?
I just got a few grams left so I think for this round I´ll mix 0.2 EC or 100ppm aquarium remineralizer + 100ppm CalMag for my base. Test 1 plant with nova next run!


Last years were very stressfull had "no time" to read into this topic... But definitely will switch to organic asap!!!!


Been to USA and felt in love.

Cheers

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Organic can be done different ways. Buy it, make your own, or a sterile medium and organic nutes. Truth be told, unless you process and harvest your own, you don't know what you are really getting.

I've been to a few countries, the USA ranks about 4th for me as far as countries go, but I like my guns lol, so here I am. That, and they make it pretty expensive to leave, as you get taxed by both countries unless you denounce citizenship. Fucking legal jockeys.

Findus said:

But how do I use it? As a base water nutrient?

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yes. for soil i'd go for maybe 4 to 8 mL per gallon range. depends what EC range you normally feed at.

something about your aquarium mineral comment has me worried about pH. fish don't like pH levels that cannabis does. most rivers are around neutral pH 7.0 i think your pH is off which is causing your deficiencies that you are seeing.