too much calmag for GH nutes?

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Can using too much cal mag cause some sort of nutrient imbalance where it locks out other nutrients or itself from being properly absorb? I've been having issues with my plants ever since I switched over from AN 3 part to GH 3 part nutes.

I use GH recommended ratio of 3 grow to 2 micro to 1 bloom for veg along with 7ml per gallon of calmag.

My plants has not been looking great, been showing signs of different deficiencies and oddly enough lack of calcium was one of them.

Totally at a lost, hoping yall could chime in and help. I'm using rock wool if that matters at all


I don't grow in rock wool....but 7ml calmag/G is a lot. Especially if using tap water. I use Gh flora series nutes quite a bit. But I only use the micro and Bloom. 6/9 is the recipe...but I only use 1/3 strength because that gets my ec to 1.2ish. My tap water is 0.6ec. I only add 1.5ml/G of calmag and I have no issues concerning food.

I would recommend a ppm or ec meter and mix your nutes to an ec of 1.2(or equal ppm) and cut way back on the cal/mag. Increase nute strength later if needed...but I think you'll find the plants don't need the amount of food the bottle tells you to use. Less is more.


I'm sorry, forgot to mention I use R/O water and a DTW system. I usually PH my nutes to 5.8 or 6.0 whichever comes first.

I'm using the grand daddy purple strain and have been told that it needs a bit more calmag than most strains.

Right now it seems like i'm suffering from various illnesses from calcium decencies to manganese to magnesium decency


Premium Member
have you checked the ppm of this?
3 grow to 2 micro to 1 bloom
this is really high but this is ok if your in soil and feed 1 time a week with regular flush but most other mediums this can cause lockouts then you add the cal/mag this boost your K and the K of bloom added together will lockout cal.
dont think I missed it did you say what your medium is ? hope this helped


Look into the lucas formula. Tons of farmers use it. Usually put 4-6ml per gallon then completely cut it out at the end of flower. Never had any problems. In my experience kush's seem to love more cal mag.

Flush then stop using the nasty green stuff.


I started running cutting edge solutions 3 part some time back and what i found was that everything that is in Calmag is already in the micro portion of the 3 part. I don't think you should use calmag unless you are running a 2 part base. I was doing just that in the beginning, and when I stopped, so did my problems. I also use carbo load(AN), budswel, green planet's massive and finisher, silica, and hygrozyme. Anyway if your using flora micro, do a side by side label check and you might find you're double dosing.


otal Nitrogen (N) 5.0 %
0.3% Ammoniacal Nitrogen
4.7% Nitrate Nitrogen
Soluble Potash (K2O) 1.0 %
Calcium (Ca) 5.0 %
Cobalt (Co) 0.0005 %
Soluble Iron (Fe) 0.1 %
0.1% Chelated Iron (Fe)
Manganese (Mn) 0.05 %
0.05% Chelated Manganese (Mn)
Molybdenum (Mo) 0.0008 %

Derived from: Ammonium Molybdate, Calcium Nitrate, Cobalt Nitrate,
Copper Nitrate, Potassium Nitrate, Zinc Nitrate, Potassium Borate,
Potassium Sulfate, Calcium Carbonate, Manganese EDTA, Iron EDDHA
and Iron DPTA.

Information regarding the contents and levels of metals in this product is
available on the internet at F-1109
elements plus special pH buffers.
FloraMicro is the foundation of the "Advanced Nutrient
System." FloraGro and FloraBloom form the structure.
Combine FloraMicro, FloraGro and/or FloraBloom in
different ratios to create specialized nutrient mixes. We
call this the "building-block" method. This unique system
gives growers greater control over the nutrient mix than
a single-part nutrient.
• An aggressive nutrient can be mixed for fast growing
plants with a high metabolic rate, or a mild nutrient can
be mixed for delicate or slow growing plants.
• Adjust the nutrient mix to meet specialized needs for
each phase in the plant's life cycle: seedling, vegetative,
transitional, flowering and fruiting.
• Refer to the Basic Applications Table for mixing
recommendations. Please measure accurately. Reduce
nutrient strength if plants show signs of stress, or if
growing in very bright, hot or dry environments.
Shake well before mixing. Always add FloraMicro to
fresh water first and stir well, then add FloraGro and/or
FloraBloom. Never combine FloraMicro with FloraGro or
FloraBloom in undiluted form; doing so may cause
nutrient lockout making some minerals unavailable.

This product is concentrated to the limit of solubility. Protect from freezing and
direct sunlight. If crystallization occurs, mix entire contents with an equal
amount of hot water and double the amount used.
Keep out of reach of children.



I think you'll find there's more calcium in your micro and everything else is pretty comparible. In other words, ditch the Calmag. :nod


Premium Member
I use a modified Lucas on tap water, love GH, been using it for years now. NO green bottle, don't need it. Micro has plenty of N already.. I would not use CalMag, I'd use Magi-Cal instead.. :)


Why would you recommend Magi-Cal over cal/mag? They are almost identical if not identical products as far as content are they not? Just curious.


To the OP- I also think that 7ml Cal/Mag is too much. We start at 1ml per gallon towards middle veg cycle and work up to a dose of around 5ml per gallon.

You want to know how much cal/mag is in your starting water for sure. Lots of growers use Cal/Mag and do not need it and then lots of growers are short on cal/mag as well which is why you need to know what your starting with in your source water and then you will know exactly how much if anything you need to add.

Start building a nutrient profile by establishing a "base" feed schedule that includes frequency and amounts(concentration levels). You then want to balance all the mineral concentrations in your base formula which usually details adding Cal/Mag and silica.

An example of building this profile with just a single formula that can be used for both veg and flower cycles with just a few changes in amounts.

i.e.- DynaGro Bloom at 2ml per gallon plus 1ml Protek plus 1ml Cal/mag

-Optional- 1ml H202 29% working up to 3ml per gallon every 2 or 3 weeks.

-Optional- 1 gram Epson Salt per gallon added at the start of the transition period.

Then increase the base formula and either add or reduce the amounts as needed (veg or flower or transition) letting the plants guide you during the weekly changes.

A few cycles of this method and you will be able to REALLY "dial in" your technique and produce the healthiest plants possible that your environment will allow. You would be surprised as to how much these little changes will make in the bigger picture and also how easy it is to really understand plant nutrition for specific type plants. Few growers take the time to learn these basic skills in feeding/schedules and instead get caught up in marketing tactics established by snake oil venders and do not be confused, they are GOOD at what they do which is marketing and not producing fine quality plants that are SAFE to consume as medicine.



I use calimagic all the time and never had a problem! I use 2.5 mil in ed very fed and I'm running 6 diffrent strains no deficiencies what's So ever...
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