How much magnesium sulfate for 50 gallons of reverse osmosis water?

HydroNito305

Well-Known Member
Well, I ended up throwing in 2oz of Black Strap Molasses which contains 20% Calcium, along with 3 cups of Epsom Salt at a rate of 1 tablespoon per gallon, which at 50 gallons is 50 tablespoons which converts to 3 cups +/-.
 

churchhaze

Well-Known Member
the fact that you're using RO water is mostly irrelevant. Almost all formulas are based on RO water.

WHAT MATTERS IS YOUR FORMULA, NOT THE WATER!!! (unless your water is HARD)

So instead of asking about how much to add to your water... how about actually telling us something about your nutrients....
 
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churchhaze

Well-Known Member
Do you have a magnesium deficiency?? I saw your plants... so you clearly know how to grow weed.... Dial it in the same way you do with everything else. These types of questions really make no sense and invite answers with 0 basis. Stop trying to force "cal-mag" (ugh) on your plants because of the common misconception that you have to make up for what RO "lacks", as if it's the water that needs to eat.
 
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churchhaze

Well-Known Member
No wait, I'm sorry, I bashed the sponsors again.. I'm so sorry. Spend all your money on botanicare products because you NEED them if you have RO water!! I promise i'm not paid to say that!
 
Those plants look great !

Molasses can over-fertilize with iron and other micros as it is a boiled-down concentrate, I would not rely on it for calcium.

Use maximum 0.25 grams Epsom salts per liter of water if used alone. (More can cause lock-out and precipitates)

A perfect Cal-Mag nutrient solution to use in every fertigation is made by mixing:

0.2 grams epsom salts (MgSO4) per liter of water
0.3 grams Calcium Nitrate per liter of water
These will not react to make gypsum (CaSO4), Mg and Ca stay dissolved.

Dry fertilizer powders with guaranteed minimum analyses on all ingredients are what commercial greenhouse growers use; I recommend these over liquid concentrates. Professional grade, dry fertilizers will cost 5% of what people pay for liquid concentrates, and they work better.

A complete nutrient solution is made from using the above Cal-Mag rates with 1.0 gram per liter of one of these base fertilizers:

Plant Prod 20-20-20 for veg.
Plant Prod 15-30-15 for bloom
Plant Prod 8-20-30 for finishing until leaching soil.

After pH buffering the complete nutrient solution will be 1200 - 1350 ppm, pH 6.8. You can mix CaNO3, MgSO4 and all in one reservoir too.
 

ruwtz

Well-Known Member
1/4tsp/gal epsom gives you 30ppm Mg and 120ppm Sulfur.

Build from there as needed.

Be sure to make solution from warm water so it's not suspended as a solid in your res.
 

Dr. Who

Well-Known Member
I'm with @churchhaze on this one here!
Your in soil.....Adding a Ca/Mg isn't needed unless your experiencing a def.....Don't see one!

The RO doesn't matter - soil!

I find Molasses as being over rated for everything.....(here comes trouble) except making AACT teas.
Higher S levels are better in bloom.
 

HydroNito305

Well-Known Member
I'm with @churchhaze on this one here!
Your in soil.....Adding a Ca/Mg isn't needed unless your experiencing a def.....Don't see one!

The RO doesn't matter - soil!

I find Molasses as being over rated for everything.....(here comes trouble) except making AACT teas.
Higher S levels are better in bloom.
I'm in soilless, and yes I had shmptoms consistent with the begining stages of Calcium and Magnesium Deficiencies, but they have all cleared up now, thanks
 

Dr. Who

Well-Known Member
I'm in soilless, and yes I had shmptoms consistent with the begining stages of Calcium and Magnesium Deficiencies, but they have all cleared up now, thanks
Soilless,,,,,Yup, I would use a Ca/Mg. I wouldn't put molasses in any soilless though! Not the best idea......No bacteria or fungus to break it down in proper ways with synthetic nutrient use. Unless of course if your adding it.
 
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