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BigDon
2010-May-12, 06:58 PM
Hi all, I need to try and replicate the magnesium content of seawater and was wondering how many teaspoon of epsom salts would you add to four gallons of water? I'm trying to encrease the solubility of calcium for my freshwater snails.

captain swoop
2010-May-12, 08:05 PM
Isn't there an aquarist board that would know?

Swift
2010-May-12, 08:15 PM
I started Googling some info, like the concentration of mag in seawater, and found this very detailed webpage (http://www.advancedaquarist.com/issues/oct2003/chem.htm). I wonder if this has your answer BD.

And even more here (http://reefkeeping.com/issues/2006-07/rhf/index.php).

If that doesn't do it, I can try to work through some calculations later.

JohnD
2010-May-12, 08:52 PM
Also Googling on your behalf, Don, I found, "One tablespoon of the salt contains about 35g (grams) of magnesium sulfate, or roughly 3.4g of elemental magnesium."
(http://www.buzzle.com/articles/how-epsom-salts-can-relieve-constipation.html)
and one tablespoon= (roughly) three teaspoons.

Seawater contains 1290 ppm of magnesium (http://www.seafriends.org.nz/oceano/seawater.htm) or 1.29gms/litre (I think)
So one teaspoon in one litre of water will contain as much magnesium as seawater - about!
The teaspoon has to be the least standardised unit there is!

So you might do better to buy some capsules/tablets from a health (?!) food shop. At least you will know the mass of the Mg compound more accurately. Magnesium is available as a medicament in several forms:
1.Magnesium Oxide 400 mg tablet (61% elemental = 242 mg/tablet)
2.Magnesium Hydroxide (Milk of Magnesia) 400 mg/5ml (42% elemental = 167 mg/5 ml)
3.Magnesium Citrate 290 mg/5ml (16% elemental = 48 mg/5ml)
4.Magnesium Gluconate 500 mg tablet (5% elemental = 27 mg/tablet)
5.Magnesium Chloride 535 mg tablet (12% elemental = 64 mg/tablet)
6.Magnesium Sulfate (Epsom Salts) 98.6 mg in 1 gram salts (10% elemental)
7.Magnesium Lactate (Mag-Tab) 84 mg tablet (12% elemental = 84 mg)
8.Magnesium Aspartate Hydroxide (Maginex) 1230 mg granules (10% elemental = 122 mg)
(from http://www.fpnotebook.com/Renal/Pharm/MgnsmSlft.htm)

Hope the snails do well.

JOhn

BigDon
2010-May-12, 09:05 PM
You guys rock!

Thanks.

Ivan Viehoff
2010-May-13, 12:03 PM
The teaspoon has to be the least standardised unit there is!
The random teaspoon in your cutlery drawer may have very variable quantity, but a standard teaspoon for the purpose of cookery recipes and taking medicine is precisely 5ml. Likewise the dessert spoon is 10ml and the tablespoon 15ml. I have a set of measuring spoons, and it is evident that the standard measuring teaspoon is actually rather larger than most cutlery. I think the trad teaspoon measure was intended to be heaped, whereas the measuring spoons are for level use.

Packets of tea-leaves often contain instructions for quantities of tea to be put ina teapot which, if followed using a measuring teaspoon, or even a typical modern cutlery teaspoon, would usually be grossly excessive. This is because they are a carry-over from instructions based on early 19th century teaspoons, from when tea was very expensive and the teaspoons used then were very tiny by modern standards.

For measuring solids these volumetric measures are not very satisfactory because the amount of empty space in a powdered or granular solid can vary considerably. I don't understand why people measure things like flour using volumetric measures, where the density can vary so much with handling.

Extravoice
2010-May-13, 12:46 PM
For measuring solids these volumetric measures are not very satisfactory because the amount of empty space in a powdered or granular solid can vary considerably. I don't understand why people measure things like flour using volumetric measures, where the density can vary so much with handling.

Probably because everyone has a measuring cup in their kitchen. Not too many people have scales.

Extravoice
2010-May-13, 12:53 PM
Hi all, I need to try and replicate the magnesium content of seawater...

For some reason, the story of the Glomar Explorer (http://en.wikipedia.org/wiki/Glomar_Explorer) flashed into my mind while reading your post.

It probably had something to do with this little bit of disinformation: Hughes told the media that the ship's purpose was to extract manganese nodules from the ocean floor.

Manganese, magnesium, it's all the same, right? :)

JohnD
2010-May-13, 04:30 PM
How can I put this kindly?
No.
Manganese, element 25.
See: http://en.wikipedia.org/wiki/Manganese

John

BigDon
2010-May-13, 04:33 PM
For some reason, the story of the Glomar Explorer (http://en.wikipedia.org/wiki/Glomar_Explorer) flashed into my mind while reading your post.

It probably had something to do with this little bit of disinformation: Hughes told the media that the ship's purpose was to extract manganese nodules from the ocean floor.

Manganese, magnesium, it's all the same, right? :)

Except too much of one (manganese) will turn all your plants purple. Seen it happen to a whole greenhouse full of Dracaena deremensis 'Warneckii' after a dummy told us he knew how to do math and solutions. A disaster at the time. A whole greenhouse full of dracaenae is a LOT of money. After a week of what the heck are we going to do about it it was decided to sell them as novelties. Worked like a charm and created a demand.

BigDon
2010-May-13, 04:39 PM
Packets of tea-leaves often contain instructions for quantities of tea to be put ina teapot which, if followed using a measuring teaspoon, or even a typical modern cutlery teaspoon, would usually be grossly excessive. This is because they are a carry-over from instructions based on early 19th century teaspoons, from when tea was very expensive and the teaspoons used then were very tiny by modern standards.

THANK YOU!

I have a couple of friends who try to make tea "according to how it should be done" and produce a product very similar to what is used to soak baseball mitts in.

For measuring solids these volumetric measures are not very satisfactory because the amount of empty space in a powdered or granular solid can vary considerably. I don't understand why people measure things like flour using volumetric measures, where the density can vary so much with handling.

Mom didn't do a lot of baking sir? If that's not the case, ever wonder why she used a sifter before measuring?

pghnative
2010-May-13, 05:03 PM
a standard teaspoon for the purpose of cookery recipes and taking medicine is precisely 5ml. Not sure if this in an American vs English thing, but 1 tsp is more like 4.93 ml. Close enough to 5ml for most purposes, but definitely not precisely equal.

Extravoice
2010-May-13, 07:20 PM
How can I put this kindly?
No.
Manganese, element 25.
See: http://en.wikipedia.org/wiki/Manganese

John

The smiley, man. Note the smiley!

Ivan Viehoff
2010-May-14, 10:30 AM
Mom didn't do a lot of baking sir? If that's not the case, ever wonder why she used a sifter before measuring?
No, we don't do that. We weigh the flour first then sift it. In Europe, recipes give solid quantities as mass, not volume. Europeans own scales, not measuring cups. Though the small stuff like spices and bicarbonate of soda is measured in teaspoons.

You can get brilliant compact electronic kitchen scales these days, just a thin round pad you put any container on, and accurate enough to weigh your overseas airmail.

But we have some nice US-published cookery books. I have written a little sticker and stuck it on the scales so we don't forget: 1 US cup = 225g

HenrikOlsen
2010-May-17, 06:54 AM
In Europe, recipes give solid quantities as mass, not volume. Europeans own scales, not measuring cups.
How does that help with such things as flour, where density is highly dependent on moisture content, while volume shows less variance?