minerals

[fish]

If I want to add potassium, natrium, calcium, magnesium. What compound is good?
I prefer the powder.
Where can I buy food grade ones?
(and what is the approx. cost?)

Thanks in advance.

[urbanfarmer]

If I want to add potassium, natrium, calcium, magnesium. What compound is good?
I prefer the powder.
Where can I buy food grade ones?
(and what is the approx. cost?)

Thanks in advance.

Fertilizers aren't food grade by definition. If you are looking for a dry powder form of these products, you can check your local gardening or hydroponic shop. You will want to find natural products that are listed as organic. You may be able to find organic gardening supplies like dried kelp, guano, or bone meal for example. They will have a wide variety, but the organic ones will be the safest. However, the hydroponic ones will also be intended for vegetable crops. Synthetic chemical fertilizers may or may not be safe to continually add to a semi-closed system, but that is for you to decide.

If by natrium you mean sodium, you can get this food grade. This would be found in common table salt. You will want a brand that does not contain iodine.

As far as magnesium, this is also sold in a form for direct human consumption. You should be able to find it as epsom salt. To my knowledge, this is the only product I know that is listed as both a fertilizer and as an item for human consumption.

[davidstcldfl]

Hi Fish, Maxi crop can be bought as a liquid or dry.
Here's an analysis at .5, 1, 2.5 & 5 tsp, respectively, per gallon of water:

pH 7.63 7.33 7.21 6.89

Conductivity (mS) 0.56 0.75 1.6 2.1

Alkalinity (ppm) 123 150 265 350

Nitrate-Nitrogen (ppm) 32 69 176 370

Phosphorus (ppm) 0 0 1 1

Potassium (ppm) 113 150 500 714

Calcium (ppm) 28 25 33 35

Zinc (ppm) 0.2 0 0.2 0.3

Copper (ppm)0 0 0 0

Iron (ppm) 0 0 0.1 0.7

For an extra boost of some 'natural potassium'... I add banana peels to my media beds. The worms love it.

[fish]

Thanks so much for the information!
I'm newbie, a lot to learn