So, let's say I wanted to make my own calcium magnesium supplements...

I've got some Calimagic on the way, so I'm covered in the short term. But I have a ton of crushed oyster shell and coral, which is super high in calcium, guaranteed to be at least like 33% calcium. So let's say I were to take some distilled or RO water. Dump some of the crushed shells in there, then measure the water with a TDS (total dissolved solids, but I think all know that) meter. What is the level of TDS I should let the water hit before I remove the water, put it in a new container, and add a solid magnesium, and again wait until the TDS hits a new higher TDS number before removing the water, and adding some general grow mix, like the General Hydroponics trio and what not.

So maybe I should wait until the TDS his 100 sitting in the crushed shells, then wait until it hits 250 after removing it and adding magnesium, then removing it and adding the GH mix. I wonder what those made up 100 and 250 numbers should really be. And what is the right type of solid magnesium I should add, or liquid if that is what I should be using?

Thanks!!!

So, it looks like Epsom Salt, which is dirt cheap, is all I'd need on the magnesium front. How much would one have to add to a given amount of water to take care of a plants magnesium needs?

Thanks!

Well lets start by stating that Magnesium Sulfate loves water. So it gets "wet" from the air. Drying it would be required to get exact numbers but away we go...

Elemental PPM (mg/l) for Magnesium Sulfate (the ate = oxygen and we aint counting that)
1 gram per gallon
Mg = 26 mg/l
Sulfur = 34 mg/l

Now lets look at calimagic (my preferred calmag supplement)
1 mL per gallon
Calcium = 13 mg/l
Magnesium = 4 mg/l
Nitrogen = 3 mg/l
Iron = 0.2642 mg/l

Typically with RO water I add 5 mL / gallon of calimagic and if growing in coco I add another 1 - 2 grams of epsom (2 in peak flower).

I buy calimagic by the gallon and put a pump on it.
I also make a epsom salt concentrate that I add 95ml of to 55 gallons to get 1g per gallon.

Remember that elemental PPM is not the exact same as the reading your pen will provide. The link in my signature will explain things and with those tools you can commence to figurin' as my grandpa would say.

See link sub in oyster for egg shell same shit

hi there what you need since this is the hydroponic section is yara calcium nitrate, magnesium sulfate, iron dtpa and ro water.

Don’t mix them together. It will precipitate.

Make sure add one salt at the time and that is completely dissolved before you add a different salt to the mix.

Dissolve the calcium nitrate first, epsom second, iron last = no precipitate

this guy explains hydrobuddy in a easier way for us:

good luck and happy growing