Epsom Salt

M

Michael Phelps

Well-Known Member
So i just started the ladys into flower, day 6. I just picked up some epsom salt to add some magnesium to my reservoir.

Anybody familiar with this? What measurements would you recommend?
 
2

24/7/420

Guest
Are you showing mag deficient?

If your going to use epsom salt for a hydro system I would apply it is a foliage feed and use calmag in the res.
 
fatman7574

fatman7574

New Member
Michael Phelps said:
So i just started the ladys into flower, day 6. I just picked up some epsom salt to add some magnesium to my reservoir.

Anybody familiar with this? What measurements would you recommend?
Click to expand...
You want to maintain about 90 to 100 ppm magnesium during budding if running a high EC of 2.6 If there is no magnesium sulfate in your nutrients that would mean adding 3.6 grams per gallon for 92 ppm. That would mean 2.7 grams for an EC of 2 for 92 ppm. Your total calcium ppm should be double your magnesium ppm.

Cal-Mag from Botanicare is 200 ppm nitrogen, 320 ppm calcium, 120 ppm magnesium and 10 ppm iron chelate. They recommend that it be used 1/4 strength each time the reservoir is changed out. So this would mean 30 ppm of magnesium or 1.2 grams per gallon for 30 ppm on top of what is already supplied my your regular fertilizer. When it comes to a system where you are not changing your reservoir regularly but are instead adding fertilizer as needed it is would have to be proportional to what ever your adding. Ie if it takes 15 ml per gallon to make fresh nutrients then add 1.2 grams of magnesium sulfate to this, or (1.2/15) = 0.08 grams of mag sulfate per every ml of regular fertilizer added. If it takes 30 ml per gallon then add (1.2/30)= 0.04 grams of mag sulfate per each 30 ml added. ie Just replace the second number in the equation for the amount of nutrients it takes per gallon of fresh nutrients. and this will tell you how much mag sulfate to add per ml of fertilizer added at each top off with fertilizer.

If you wish to mix up some Cal-mag here is the recipe for 1 gallon of 100X concentrate. The calcium nitrate should be available at any green house supply store or any good hydro store. The iron chelate you can usually just leave it out. Typically it is sold in 5 pound bags. for around $50. It takes along time to go through 5 pounds. ie about 60 gallons of cal-mag 100x concentrate or about 300 gallons of a 100X concentrate of a regular full nutrient formula.

ppms
Nitrogen 200
Magnesium 120
Calcium 259
Sulfur 160
Iron 10.00

Grams
Calcium Nitrate 488.9
Magnesium Sulfate 464.0
Iron Chelate 38.57

Volume of Stock Solutions 1 gallon

Dilution Rate 100
 
D

Dirt Bag

Member
fatman7574 said:
If you wish to mix up some Cal-mag here is the recipe for 1 gallon of 100X concentrate. The calcium nitrate should be available at any green house supply store or any good hydro store. The iron chelate you can usually just leave it out. Typically it is sold in 5 pound bags. for around $50. It takes along time to go through 5 pounds. ie about 60 gallons of cal-mag 100x concentrate or about 300 gallons of a 100X concentrate of a regular full nutrient formula.

ppms
Nitrogen 200
Magnesium 120
Calcium 259
Sulfur 160
Iron 10.00

Grams
Calcium Nitrate 488.9
Magnesium Sulfate 464.0
Iron Chelate 38.57

Volume of Stock Solutions 1 gallon

Dilution Rate 100
Click to expand...
Excellent post.
To clarify, I'd use 1/400th gallon of your 100X per gallon of reservoir to achieve the recommended 1/4 strength? Or in my case (100gallons) 1 quart?
Also, have you used Calcium Chloride in place of Calcium Nitrate? Could this be a better choice for the later flowering? I have both on hand along with a severe calmag deficiency right around the 4th week of each new 400L reservoir. Something I've only been experiencing since going to RO.
 
Michael Huntherz

Michael Huntherz

Well-Known Member
fatman7574 said:
You want to maintain about 90 to 100 ppm magnesium during budding if running a high EC of 2.6 If there is no magnesium sulfate in your nutrients that would mean adding 3.6 grams per gallon for 92 ppm. That would mean 2.7 grams for an EC of 2 for 92 ppm. Your total calcium ppm should be double your magnesium ppm.

Cal-Mag from Botanicare is 200 ppm nitrogen, 320 ppm calcium, 120 ppm magnesium and 10 ppm iron chelate. They recommend that it be used 1/4 strength each time the reservoir is changed out. So this would mean 30 ppm of magnesium or 1.2 grams per gallon for 30 ppm on top of what is already supplied my your regular fertilizer. When it comes to a system where you are not changing your reservoir regularly but are instead adding fertilizer as needed it is would have to be proportional to what ever your adding. Ie if it takes 15 ml per gallon to make fresh nutrients then add 1.2 grams of magnesium sulfate to this, or (1.2/15) = 0.08 grams of mag sulfate per every ml of regular fertilizer added. If it takes 30 ml per gallon then add (1.2/30)= 0.04 grams of mag sulfate per each 30 ml added. ie Just replace the second number in the equation for the amount of nutrients it takes per gallon of fresh nutrients. and this will tell you how much mag sulfate to add per ml of fertilizer added at each top off with fertilizer.

If you wish to mix up some Cal-mag here is the recipe for 1 gallon of 100X concentrate. The calcium nitrate should be available at any green house supply store or any good hydro store. The iron chelate you can usually just leave it out. Typically it is sold in 5 pound bags. for around $50. It takes along time to go through 5 pounds. ie about 60 gallons of cal-mag 100x concentrate or about 300 gallons of a 100X concentrate of a regular full nutrient formula.

ppms
Nitrogen 200
Magnesium 120
Calcium 259
Sulfur 160
Iron 10.00

Grams
Calcium Nitrate 488.9
Magnesium Sulfate 464.0
Iron Chelate 38.57

Volume of Stock Solutions 1 gallon

Dilution Rate 100
Click to expand...
I would mix the calcium nitrate and mag sulfate in separate vessels until ready to add to the reservoir, otherwise you will get a lot of gypsum precipitate. You want to keep them separate until diluted or you will end up with little white rocks in the bottom of a magnesium nitrate solution.
 
Last edited:
DrBlaze

DrBlaze

Well-Known Member
Dirt Bag said:
hoped to raise some new posts regarding chloride vs nitrate
Click to expand...
Nothing wrong with keeping old threads going, if they've got good info. I miss having fatman around.

I use calcium chloride for my rdwc system. You can get a great deal on it from amazon. Snow Joe ice melter (the red bag) is pure calcium chloride. It dilutes fairly quickly and a side benefit is the chloride which is a beneficial micronutrient that a lot of nutrients lack. If you look outside of the marijuana nutrient market you will see that many calcium additives (including many of the organic ones) are made from a calcium chloride brine. Another benefit is being able to add calcium in the last weeks of flower without the big surge of nitrogen you will get with most cal-mag additives.
 
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