Mag supplements

Discussion in 'Reef Chemistry' started by neuro, Jun 28, 2015.

  1. neuro

    neuro Webmaster

    Hey All,

    I'm thinking about buying magnesium in bulk.

    Randy Homles has a guide to what to buy and what to dose. I'm going with Mag Flakes and Epsom salt mix:

    Ebay has both, and it's relatively cheap to get A LOT. By a lot I mean this:

    Anyone have any experience doing this on your own? I use magnesium almost as much as I use Alk and Calcium.

    @Nav and I may go in on this together.
  2. gaberosenfield

    gaberosenfield Juvenile Chromis over an Acro in the Red Sea

    I'm just curious, but why do you need to dose so much magnesium in your setup? What salt are you using? Do you not do water changes or something?

    I sometimes dose some MgCl2 if a new batch of saltwater from a new box of salt tests a bit lower than I like. Maybe I'm just paranoid, but the idea of dosing mag flake designed to de-ice roads or epsom salts designed to soak your feet or fertilize plants scares me. There is no need for the manufacturers to ensure much purity of their products. Considering that MgCl and MgSO4 are both available in bulk from BRS at cheaper prices than the ebay links you posted (, I would buy them over products designed for fertilizer and de-icing. Maybe there will be no problem with the products you linked, but this is my two cents.
  3. Klems

    Klems Supporting Member

    And BRS has new lower shipping costs and faster delivery then in the past...
  4. Enderturtle

    Enderturtle Volunteer


    I haven't read neuros link but Randy Holmes is a famous chemistry guru in the reef keeping hobby.

    He has written several guides/articles related to the application of chemicals/explaining chemical process in the reef aquarium and currently has his own subforum on reef2reef where he answers questions. I'm betting the owner of reef2reef pays him to do this or maybe he does it for free. So if randy holmes says epsom salt is a reef safe alternative for supplementing whatever it does, then it most likely is.

    His articles and posts are legit/dependable.

    I imagine the chemicals mentioned in the article are significantly cheaper than the branded chemicals listed on BulkreefSupply. Which is the motivation for people to do it.

    Magnesium, alkalinity, and calcium uptake is gonna vary from tank to tank right? A 60 gallon tank housing a bunch of acroporas/montis is going to use up calcium and alkalinity and magnesium way faster than a tank with a bunch of LPS corals. I'm going through a little coraline algae bloom right now too so I'm noticing my magnesium/alkalinity/calcium drop faster than usual.
    neuro, jonmos75 and Nav like this.
  5. gaberosenfield

    gaberosenfield Juvenile Chromis over an Acro in the Red Sea

    All true, and I am familiar with and have great respect for Randy Holmes Farley. However, as I said, the Mg supplements being discussed are cheaper from BRS than from the sources the OP linked. And even though RHF used mag flake and Epsom salt, it can't be worse for your tank to use higher purity products. Of course the BRS products might not be higher purity, but it seems like a fairly safe assumption since their products are designed to be used in reef tanks rather than on roads.

    As to the point about different tanks need different things, of course I agree. However, it is my understanding that no coral uses more magnesium in its skeleton than calcium. And by definition, no coral can use more magnesium than carbonate equivalents. Therefore it seems odd to me that the OP said they've been dosing more magnesium than calcium or alkalinity. I'm not saying you're doing anything wrong, just curious what they think is going on.

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  6. Coral reefer

    Coral reefer President

    Aquatic collection carries the mag chloride and mag sulfate.
    neuro likes this.
  7. Nav

    Nav Director of Marketing & Photography

    Alfred said "I use magnesium almost as much as I use Alk and Calcium", not more than Cal/Alk. I would think depends on the salt you're using and where you keep your Mag level at. I've seen people happy with 1200, I do 1350-ish, some I heard do 1450...
  8. gaberosenfield

    gaberosenfield Juvenile Chromis over an Acro in the Red Sea

    My bad on the misreading (or not reading, lol) of the original post. Makes more sense now.

    Sent from my SAMSUNG-SM-G870A using Tapatalk
  9. neuro

    neuro Webmaster

    thanks all.

    My tank has super heavy bio load. @Nav can attest to that.

    I use a lot of alk and a lot of calc. My magnesium dips below 1100 by the end of a week if I don't add at least 1/3 or 1/2 a cup of the BRS mag mix everyday. I try to keep it at 1200+, if not 1290. I use up to 1 gallon of the BRS alk mix up after 2.5 to 3 weeks in order to keep my ALK at 9.3 Kdh. My calc dose is almost as much in order to keep at ~400.

    If I keep mag at ~1200, my Zoas and plating SPS do extremely well. Don't ask me why, but for some reason, if my mag is at least 1200, I get full sized zoa expression, and my plating SPS exude extreme colors. Any less than 1100 for a duration of time, results in STN.

    @gaberosenfield You may be right that I may have something wrong in my tank (I have extreme calcification), but for some reason, after months of testing and trying different things out, I have come to the conclusion that this rate of consumption is the only way I can balance my tank.
    Nav likes this.
  10. gaberosenfield

    gaberosenfield Juvenile Chromis over an Acro in the Red Sea

    Wow! You must have crazy growth of TONS of corals! I retract all my previous comments about this seeming strange. The only strange thing must be your coral bioload and growth rate. I really need to figure out why I'm struggling so hard with issues in my tank...

    Good luck finding the cheapest magnesium supplement!
  11. neuro

    neuro Webmaster


    I ordered the mag flakes and epsom salts from better and less expensive alternatives on ebay. total came out to about ~$65 or so

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