Found something on the Net that I just NERdED out on Big time.. Sort of understand it, it was posted in 2012
Hello, people!
“it is a fact that cal mag is necessary for optimum growth. Just ask any commercial or professional grower.”
Well, yes, that's true, but I am a professional grower and I don't use any calcium or magnesium supplements because I don't have to. That's because I use a nutrient that already contains more than adequate amounts of each and I run ph at levels that allow for sufficient uptake. In the greenhouse hydro industry growing tomatoes with drip irrigation in perlite culture many operations use bulk nutrient preparations that are dry and come in two parts. One part contains everything but calcium nitrate, the other part is calcium nitrate. They keep them separate to prevent magnesium sulfate and calcium nitrate from interacting. Just as the gh flora series, techniflora nutes and many others do, liquid or dry. The one part flora nova gets away with everything in one bottle as it is a colloidal suspension that separates during storage, thus preventing the interaction. However, there are many nutrient packages that don't contain sufficient cal-mag. Pure blend pro is a classic example. You absolutely must use cal-mag with it to avoid disaster.
I am currently using maxibloom for flowering. It is a one part product that does not have any reactions until you put it into solution in water. It contains ample amounts of cal-mag.
The calcium/magnesium deficiency most folks run into eventually using hydro nutes is caused by ph being maintained at levels that don't allow for decent uptake. Not by the nutrients being low on either calcium or magnesium.
I know I run the risk here of opening up a whole can of worms on proper cannabis hydro ph, but here goes anyway.
Most of the ph charts you see are incorrect or misleading. Most would have you believe that if you don't run at a specific ph you are running the risk of lockout of one element or the other. Some depict uptake of elements at different ph points that don't even overlap with their recommendation for ideal ph, usually at around 5.8.
The truth is that there is no such thing as ideal ph and there are no finite points where lockouts occur. Every application is a compromise. However, the 5.8 recommendation is right in the middle of the range where you get the least calcium and magnesium uptake. You are still getting some, but usually not enough. You either have to get above 6.0-6.1 or below 5.5 to get adequate uptake of calcium or magnesium. I believe that above 5.5 phosphorus availability starts diminishing so I start my input solution at 5.2. As nutrients are used and evaporation/transpiration occur the ph will climb. The girls love it and show no symptoms of deficiency.
So, if you are using ro or distilled water and your nutrient shows calcium and magnesium on the label try running your ph between 5.1 and 5.4 for a while and see what happens. I think you will be pleasantly surprised.
If you are using ro water it is probable that you have very hard water from your tap and you decided to use ro water to solve the problem. If your tap water is over 200 ppm at the .5 conversion (milwaukee meters), you probably have too much calcium in your water. The calcium in your tap water plus the calcium in your nutrient solution can add up to an over abundance of calcium. An excess of calcium can cause a magnesium deficiency. You see the mag deficiency first and you think you need more magnesium so you add cal-mag thereby aggravating the situation. You can run into a similar scenario adding epsom salts (magnesium sulphate) to your solution. Too much of one nutrient can cause problems with uptake of another.
If your tap water is below around 150 ppm and doesn't contain more than 70 ppm calcium (only a water analysis can tell you this) try correcting ph to 5.2 for a while. With Ro water, if your nutes show Mg and Ca on the label, try 5.2 for a while.
Or you can blend ro water and tap water in proportions that get your tds below 100 ppm, then try 5.2 for a while.
My tap water is slightly over 200 ppm most of the time, so I blend tap 40%/ro 60% and end up with a reading of around 80 ppm before nutes are added. I chose this ratio because of the ph buffering capability inherent in the tap water mixed with ro at this ratio allows me to get away without using ph adjusters, either up or down. 2 gals tap plus 3 gals ro plus 2 level tablespoons maxibloom gives me 5.2 at around 950 ppm every time. I have visually perfect plants showing no signs excess or deficiency.
(Could very well just be the phenotype or luck of the draw with this plant) Hate to see it but all part of growing. NExt!
