Magnesium confusion

Discussion in 'General Discussions and Advice' started by viper357, 27 Feb 2010.

  1. viper357

    viper357 Admin MASA Contributor

    Joined:
    4 May 2007
    Posts:
    27,991
    Likes Received:
    782
    Hi Hennie

    Can you perhaps clear up something for me please. I am in the process of purchasing some chemicals and I have come across Magnesium, now from my understanding, a build up of sulphate from dosing Magnesium sulphate can be a bad thing, Magnesium Chloride is the better one to dose apparently. If that is the case then why do they sell a packet of MG Chloride and a packet of MG Sulphate, surely you only want the chloride? Or is it advisable to buy both and mix them together? I believe that a lot of the commercially available magnesium additives are roughly 1 part chloride to 10 parts sulphate. I'm inclined to buy just the chloride one but I'm not 100% sure.

    To be exact, the products are called:

    Magnesium Sulphate Heptahydrate MgSO4 7H2O
    Magnesium Chloride Hexahydrate MgCl 6H2O

    Thanks.
     
  2. AdS Guest




    to hide all adverts.
  3. Difficult marine

    Difficult marine

    Joined:
    18 May 2009
    Posts:
    241
    Likes Received:
    1
    Location:
    cape town
    sorry..if i didn't make mistake according reef central Randy is 10 part chloide..1 part sulphate
     
  4. Reef Maniac

    Reef Maniac MASA Contributor

    Joined:
    15 May 2007
    Posts:
    2,899
    Likes Received:
    112
    Location:
    Bloemfontein
    Viper,

    Let's rather say that an excess of sulphate is a bad thing (just like an excess of anything else...). Adding only Epsom salts (magnesium sulfate) to boost magnesium raises sulfate about four time more than it does magnesium, resulting in an excess of sulphate over time. Using only magnesium chloride to raise magnesium will result in a drop in the sulphate level of the water over time, as many bacteria and other biological processes use sulfur in one form or another, and the chloride tends to increase the salinity of the water over time. Many of the commercial salt mixes are also deficient in sulphate, and this tends to compound the problem if no sulphate is added.

    It is thus better to dose both the magnesium sulphate AND the magnesium chloride, in a ratio as close to that of natural sea water as possible. The ratio of chloride and sulfate naturally present in seawater is 7.1 to 1 on a weight basis and 9.6 to 1 on a per ion basis.

    That is correct - the ratio is 10 parts "Mag flakes" (magnesium chloride hexahydrate) : 1 part "Epsom salts" (magnesium sulfate heptahydrate) PER VOLUME. I stress the per volume, as the densities of the two products differ, and a different ratio would apply per mass. Also, this ratio is based on a specific magnesium chloride product available in the USA. It is possible that products available here in South Africa, or in the UK, could differ in loose bulk density, and could thus require a slightly different ratio. Personally, I don't think the differences would be significant, though, and I would use the same ratio if I did not have specific data on the other products.

    Hennie
     
    viper357 likes this.
  5. Nemos Janitor

    Nemos Janitor

    Joined:
    7 Feb 2009
    Posts:
    8,384
    Likes Received:
    286
    Location:
    Joe's Mountain
    If i can add a little here. When dosing do not dose to raise Mg by more than 30ppm per day. If you do you will end up with Ammonia issues.
     
  6. mariusmeyer

    mariusmeyer

    Joined:
    7 Jul 2009
    Posts:
    3,055
    Likes Received:
    210
    Location:
    Jukskei Park, JHB
    I have added magnesium up to 100ppm a day without any issues. But I did have very little livestock in the tank.
     
  7. Difficult marine

    Difficult marine

    Joined:
    18 May 2009
    Posts:
    241
    Likes Received:
    1
    Location:
    cape town
    my fish tank used 100ppm per weeks and i used seachem advance magnesium...but the amount of money is kill me per month....they why i try used local magnesium chloride and magnesium sulfate...the way much much cheaper
     
  8. viper357

    viper357 Thread Starter Admin MASA Contributor

    Joined:
    4 May 2007
    Posts:
    27,991
    Likes Received:
    782
    Thank you Hennie and everyone else, perfect :thumbup:
     
  9. Mekaeel

    Mekaeel Moderator MASA Contributor

    Joined:
    8 May 2007
    Posts:
    24,229
    Likes Received:
    127
    Location:
    Point Waterfront Durban
    Hi Hennie!
    Can Magnesium Chloride be purchased from the local chemist?
     
  10. Reef Maniac

    Reef Maniac MASA Contributor

    Joined:
    15 May 2007
    Posts:
    2,899
    Likes Received:
    112
    Location:
    Bloemfontein
    Hi Mek,

    I don't think so - well, not here in Bloemfontein, in any case. I buy my supplies from one of the industrial/laboratory chemical suppliers - either Merck Radchem or Minema whoever is the cheapest at the time.

    This reminds me, I'm about due for a new order of magnesium chloride, sodium carbonate, calcium chloride and calcium acetate, so I will be asking for quotation again soon. If anyone is interested, I will post the info on MASA.

    Hennie
     
  11. viper357

    viper357 Thread Starter Admin MASA Contributor

    Joined:
    4 May 2007
    Posts:
    27,991
    Likes Received:
    782
    Why the two different calcium's? I'm buying some Calcium Chloride Anhydrous.
     
  12. Mekaeel

    Mekaeel Moderator MASA Contributor

    Joined:
    8 May 2007
    Posts:
    24,229
    Likes Received:
    127
    Location:
    Point Waterfront Durban
    Thanks alot Oom! :) I will speak to Preshan, I know he has a contact somewhere. Thanks once again.
     
  13. mandarinman

    mandarinman

    Joined:
    18 Oct 2007
    Posts:
    6,377
    Likes Received:
    70
    Location:
    capetown,durbanville
    please explain the two calciums
     
  14. Reef Maniac

    Reef Maniac MASA Contributor

    Joined:
    15 May 2007
    Posts:
    2,899
    Likes Received:
    112
    Location:
    Bloemfontein
    The calcium chloride is the normal "turbo calcium" sold by the pet shops at exorbitant prices.

    The calcium acetate is the chemical equivalent of adding lime water spiked with vinegar. It can be added directly to the tank (in a high-flow area) and does not rapidly upset the pH when added (unlike lime water). It is a very handy product to keep in stock to tweak the calcium and alkalinity without upsetting the ionic balance of the water (unlike calcium chloride) - in fact, it is a "one compound" balanced additive, and could be used as the only additive if the calcium/alkalinity demand is low to medium. It also adds a carbon source to the water, due to it's reaction with CO2 in the water, which does the same job as Vodka, feeding your bacteria.

    Hennie
     
  15. Johan van Aardt

    Johan van Aardt I love marines [R.I.P.]

    Joined:
    11 Jan 2009
    Posts:
    1,436
    Likes Received:
    4
    Location:
    cape town, table view
    i want some of that!!!!!!!!
     
  16. mandarinman

    mandarinman

    Joined:
    18 Oct 2007
    Posts:
    6,377
    Likes Received:
    70
    Location:
    capetown,durbanville
    R 785 per 25 kg ex vat if four other guys want to divy with me. ps i have digital scale.
     
  17. Mo_G

    Mo_G MASA Contributor

    Joined:
    7 May 2007
    Posts:
    267
    Likes Received:
    3
    Location:
    Benoni
    can calcium acetate be added in the same way as lime water via a reactor?
     
  18. Reef Maniac

    Reef Maniac MASA Contributor

    Joined:
    15 May 2007
    Posts:
    2,899
    Likes Received:
    112
    Location:
    Bloemfontein
    Hi Mo G,

    Apologies for only responding to this thread now, but I've been away from home for the past three weeks, and have only returned home this evening...

    To answer your question: No.

    Calcium acetate is highly soluble, and one can dose it by adding the dry powder directly to a high-flow area in the tank, such as in the overflow box/weir, or at the discharge point in the sump (obviously not where the undissolved powder might land on a coral, as it does take a second or two to totally dissolve...)

    Hennie
     
  19. SchyffS

    SchyffS Reef Aquarist

    Joined:
    26 Jan 2008
    Posts:
    588
    Likes Received:
    12
    Location:
    Cape Town
    Hello Oom ;)
    Im a little confused with the per volume and density explanations....Randy Holmes explains per cup, can i stick to this rather.

    Recipe #1, Part 3A
    Dissolve Epsom salts (3 cups) and magnesium chloride hexahydrate sold by the Dead Sea Works company (5 cups) in enough purified freshwater to make 1 gallon total volume.
     
  20. mariusmeyer

    mariusmeyer

    Joined:
    7 Jul 2009
    Posts:
    3,055
    Likes Received:
    210
    Location:
    Jukskei Park, JHB
    Please help me with this issue. When using magnesium chloride to raise the magnesium levels, you said that the salinity also increases over time. But what about epsom salts? Does it also raise the salinity? I need to boost my magnesium levels in order to help with bryopsis. Using epsom salts to raise magnesium by 300ppm in 600L of water is a lot cheaper than to use proper magnesium supplements. Of course I will use better supplements once the levels are higher for maintenance purposes.
     
  21. sweetnsour

    sweetnsour

    Joined:
    15 Jul 2009
    Posts:
    1,728
    Likes Received:
    8
    Location:
    JHB East Rand
    Marius if using the epsom salt keep up the water changes dude @ least 30% per month
     
Recent Posts

Loading...
Similar Threads - Magnesium confusion Forum Date
Epsom salts / Magnesium General Discussions and Advice 25 Oct 2015
[wtd] Tech M Magnesium Wanted 9 Oct 2015
Water parameters - calcium, magnesium and alkalinity Beginner Discussions 13 Aug 2015
Magnesium General Discussions and Advice 23 Jun 2015
Thinking about buying Salifert Test Kit Magnesium? Read our latest review of the... JungleAquatics.NET BLOG 26 Apr 2015
Thinking about buying Seachem Reef Advantage Magnesium? Read our latest review o... JungleAquatics.NET BLOG 4 Apr 2015
Wanted:Kent Marine Magnesium Water Parameters and Additives 11 Mar 2015