Can't keep Magnesium levels up

Saltynoob

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I've been dosing my tank for the last couple months with magnesium. When I first started tracking my Mg levels, it was running about at 1000ppm. It took me a couple weeks to get the level up up in the 1350ppm range. The problem I'm having is that I can't keep the level up if I don't dose daily. A little bit of back story. When I first setup my tank in February, I used Seachem Marine salt; initial testing showed I had a Ca level of about 440-460ppm. I swapped over to Reef salt since my intention was to run a mixed reef tank. Since then, my Ca levels jumped up to 560-580ppm, and it has remained rock steady there ever since mid April. I've tested with two different test kits and took a sample in to the LFS to verify. I even brought a sample to work and tested it at the lab here.

My alk runs between 9 and 10, pH about 8.26-8.35. I dose about 100mL of the BRS mix daily and may have to increase this volume because it's slowly dropping.

I have read that chaeto consume a lot of Mg, and I have some in my fuge. As far as coral I have a 2" piece of green birdsnest, a 2" piece of red birdsnest, a war coral, an elegance coral, a GBTA, a maxi mini, various mushrooms, some zoas, and a leather of sorts.

any suggestions or ideas would be greatly appreciated
 

beaslbob

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How much are you dosing?

I would follow the diy 2 part system.

I takes a lot of magnesium to correct years of not dosing especially that first adjustment. In my 55g years ago mag was down to 800ppm. I took 3 pounds (or so) of epson salts to get it to 1300ppm. Other locals here report similiar experiences and all those agree with the reef chemistry calculator.

Once I started the diy two part, I found magnesium followed the recommended procedures precisely and no additional adjustments were necessary.

my .02
 
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Saltynoob

Saltynoob

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I'm dosing 100mL of the BRS two part Mg mix. I've only had this tank running since Feb. of this year. I've been able to get the [Mg++] up to 1300; I just can't keep it up there unless I'm dosing daily.
 

VegasRick

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Whats the Mg level in the sw mix you use. I doubt if your system is using very much. You are probably lowering it when you do water changes. The estimates on Mg consumption run around 2 ppm per day for a mature reef with sps and good coraline algae growth. For a new tank with a sand bed your usage may be higher as it bonds with the sand but should stabilize after a short period.
 
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Saltynoob

Saltynoob

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Are you dosing 100ml of each component (alk, Ca, mag) ?
No, just 100mL of the Mg mix.

Vegas, according to the seachem site, Mg in Marine salt mix is 1317ppm. I tested it today and the reading was 1353. That was a 50ppm increase from my tests on 6/7.
 

MoneyPit

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I recommend that you just continue to dose daily. I dose once a week in between my weekly water change. As for what the Seachem website says, the Mg level will fluctuate some in the salt mix from batch to batch. You should test your saltwater mix before you change it out to make sure.
 
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caudill187

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+1 lowering Mg++ with water changes, unless you are dosing kalkwasser (which can precipitate Mg++ in my experience). Just dose as much as you need. I use Reef Crystals which averages significantly less Mg++ than I want and dose what seems like way too much Mg++. In general, Mg++ supplements are not very potent and any Mg++ increase requires a very large volume of supplement.
 
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Saltynoob

Saltynoob

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Thank you all for the replies. It appears I've reached the point of stabilization for now. I haven't dosed in 4days (partly because I was trying to determine my actual consumption), and my [Mg++] has quit dropping. It actually when up from my last reading. It is sitting at 1500ppm. I'll let it sit for another four to five days and see if it what it does. On the plus side, I have actually seen a drop in my [Ca++]. We will see what all happens in the next few days.
 

treylane

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Just to throw in my two cents... my tank was never properly stable until I bought the @#% third doser and started dosing mag daily. IME / for my tank, that whole "mag is not that important, only need to dose monthly" thing mentioned in the twopart articles, was total hogwash.
 
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