Low Mag

[Parker]

Hi All,

Tested my Mag last night ( Brand New Elos Kit ) and got results of 400. My WC water tests around 700 or so, I try to change at least 65-70 gallons every week but I've missed the last few weeks.

What would cause my mag to drop this low? Alk and Calc are within spec. All tested with ELOS kits that are fairly new.

I'm a bit of a dunce when it comes to chemistry sometimes.

Thank!

[Delphinus]

Magnesium gets used up by critters the same as does Ca and Alk (the depletion rate is much slower than that of Ca and Alk but without dosing it will eventually be a downward trend).

700 is kinda low to begin with (although not surprising, many salts seem to come with low Mg unless it's one specifically marketed at having higher levels.). Seawater is something like 1280. I like to keep mine a little bit around 1400 because I think my anemones look better when Mg is there. What I do is add Mg to my waterchange water, I figured out how much to add everytime to make my waterchange water around 1500-1600 and then when I do a water change it bumps Mg up in the tank a little bit (not by much since I can only do about a 8.5% waterchange at a time).

[Myka]

I have yet to find a salt mix that has enough magnesium in it, although I hear the Reefer's Best does. Anyway, the Mg is probably that low because your salt mix is low, plus the inhabitants are using it up. Do like Tony suggests by increasing the Mg in the freshly mixed saltwater before the waterchange.

[Parker]

That's what I find wierd, should it have dropped to 400 in the first place? I'm keeping up Alk and Calc via waterchanges so it stands to reason that if Mag is depleted a lot slower it should be holding at around 700, no?