First Dowflake, now Magnesium...too cool - GROUP BUY FOR NOV MEETING
This is an UNOFFICIAL group buy, meaning it has nothing to do with the BRS or it's sponsors, I set it up myself.
Group buy on Magnesium Chloride
WHY DO YOU NEED IT?:
Over time tanks can slowly become depleted in their magnesium levels. Certain corals, and coralline algae remove magnesium from the water quickly. The easiest way to bring the magnesium level back in many tanks is just to do more water changes. For very large tanks the amount of water changed to get back in balance could be very large. Also, some artificial salt mixes tend to be a bit low in magnesium. Natural seawater concentrations of magnesium are around 1350 ppm. IME, it's not good to allow the level in tank to drop below 1200 or so. In a frag tank I once had it drop to 1000 ppm, and a lot of things were looking very ill. Once corrected things started looking better in one day. More info on magnesium and it's role in a reef tank can be found here: Magnesium in Reef Aquaria
http://www.advancedaquarist.com/issues/oct2003/chem.htm
WHERE YOU COULD GET IT:
You could purchase B-ionic magnesium (one of the least expensive Magnesium supplements), but for a large tank this runs into big money fast (the cost of the supplement I'm describing below is about 1/30th of B-ionic Magnesium).
You could also use Epsom salts, the problem with this is that Epsom salts are magnesium sulfate heptahydrate, which means you are adding a lot more sulfate to the water than you should be (more on this later), and over time your tank may get a bit out of 'whack'. If you are using Randy-HF's two part calcium/alkalinity supplement this is less of a concern due to the formulation of the supplement, but even then, over time the sulfate in your tank will become elevated over time if you only use magnesium sulfate.
You could make a magnesium supplement yourself. I can show you how to do it. Craig Bingman wrote an article about how to do it years ago. A Homemade Magnesium Supplement
http://web.archive.org/web/200306242...io/default.asp
The formula below creates a magnesium supplement that does not significantly create an imbalance in any other anions in your tank's water. The anions in saltwater are chiefly chloride (Cl-) and sulfate (SO4-2). Bromine is also in there as an anion, but it's slow low that for many years salt manufacturers never even bothered to add it to their mixes, so leaving it out of this supplement is not a big deal at all. The basic formula is:
664 grams MgCl2.6H2O
113 grams MgSO4.7H2O (Epsom salts, from the drug store costs $1.99 for 3 lbs)
plus enough DI water to make 1 gallon.
or if you want to do it on a larger scale, using pounds to weigh stuff out:
1.5 lbs MgCl2.6H2O
0.25 lbs MgSO4.7H2O (Epsom salts)
plus enough DI water to make 5 gallons
you don't need to be super accurate on the weighing.
Adding this at the rate of about 10 ml/gallon of tank volume (in a stream of water where it will get mixed into the tank quickly) will increase the magnesium level in your tank by about 100 ppm. It's never a good idea to make changes too fast to a tank's water chemistry, so if your tank is low in magnesium by more than 100 ppm I'd still only add 10ml/gallon/day until you are back around 1250-1350 ppm. So, for instance, if your 100 gallon tank were 300 ppm low in magnesium, you'd need about 3 liters, or almost 1 gallon of this solution to get back into the proper range on magnesium.
To dose magnesium correctly you really need to measure it with a decent test kit. I've found the Salivert kit for magnesium to be pretty good and reasonably priced, FWIW.
BUT NOW I NEED THIS MgCl2.H2HO STUFF, WHERE WOULD I GET THAT?!?:
I have contacted a major supplier of high grade magnesium chloride, that apparently supplies the same grade of magnesium chloride to about 70% of the artificial salt mix manufacturers. I will post a copy of the typical purity analysis that comes from this grade of magnesium chloride at the bottom of this message. I posted and discussed the contaminant levels many months ago on Randy H-F's chemistry forum on Reef Central, and he was confident that it was a high quality material suitable for the purpose of increasing magnesium in a reef tank. The manufacturer has agreed to ship directly to our club (or wherever we want) 48 - 50 lb bags of this material. This is the minimum order direct from the manufacturer. The final DELIVERED price will be $16 per 50 lb bag. Although this is high quality magnesium chloride, at this price it is about the same as ice melt magnesium chloride, or rock salt, etc. It is perfectly acceptable to be used as an ice melter, and will melt ice/snow better than standard rock salt because magnesium chloride will work down to -15 F. So, buy yourself a bag and use any extra to melt the ice on your driveway that you know is coming!
Magnesium chloride hexahydrate is very hydroscopic (or is it hygroscopic?)...anyhow, it attracts water, so if you purchase a bag you should plan to transfer it to an sealed container of some sort within a few weeks (I use old Instant Ocean buckets for this). As it attracts water it can kind of turn into a solid block of salt, but it is still fine to use, it's just a pain to chip it out! It never really goes, or could go 'bad'. It is a very stable chemical.
So, I'm trying to round up enough folks that would be interested in a bag or two or three of this stuff. You could give it away to your relatives for ice melt for Christmas!!! I already have several people that are interested in a bag (Randy H-F and many others), but I'm a long way from using up 48 bags. My plan is to have this stuff delivered to the Boston area in time for distribution at the November meeting north of Taunton. If you are interested please try and take a full bag and give the extra away to someone for ice melt, or use it yourself.
Now is your chance to get in on this. A lot of people still ask me about how they can get some of the calcium oxide (bulk quicklime) that we had a group buy on years ago, don't come asking me 6 months from now for magnesium chloride, this is a one time buy! I'm not taking orders for partial bags.
I have already checked with several of our local sponsors, none are interested in organizing this (though a few are interested in a bag or two), it is not a normal aquarium product anyhow, this is DIY territory.
Also, please remember, I'm NOT making any money on this. I need the stuff myself (remember? I'm a cheap bas#@$#), and am organizing this group buy for club members, so please don't make it difficult for me.
SO THE DETAILS AGAIN:
- $16 for a 50# bag - the extra you can use to melt ice (no partial bags)
- available at the November Taunton meeting, or picked up someone in the Boston area to be determined
- email me DIRECT at maggroupbuy @ greghiller.com if you want a bag (you can post below, but I will not save any for you unless you email me at that address)
- in the email please give 1. Your REAL name, 2. How many bags you want
Additional questions I'll be glad to try and answer below. I'll try and get Randy H-F to follow this thread as well. There is a thread on Randy's forum on RC which discusses the search for an inexpensive magnesium supplement. http://reefcentral.com/forums/showth...5&pagenumber=2
Trace Element Content of Dead Sea Works
Magnesium Chloride
Element Typical(ppm) Maximum(ppm)
Mg 115000(11.5%) 125000 (12.5%)
Ca 7000 8000
Br 5000 8000
K 2500 3500
S(SO42-) 180 200
Sr 120 150
B 20 30
Li 10 15
N* 4 5
Si 9 15
Fe 3 10
P 2 3
Mn 2 3
Al 1 3
Ba 1 2
Co <1
Cr <1
Cu <1
F <1
Mo <1
Ni <1
Se <1
V <1
Zn <1
As <0.1
Hg <0.1
Pb <0.1
Cd <0.01
I n.a
Rb n.a
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Originally Posted by jacko
