Best way to lower magnesium?

[Beverly]

Jason,

How big is your tank? Did you add the Mg all at once (like dump it into the tank or sump), or did you add it bit by bit in a high flow area in the tank, or what?

I don't have a sump to add my additives to, so I calculate how much additive I need with the The Reef Chemistry Calculator, and add it 10 mls at a time with a baby medicine syringe into high flow areas in my 120g. Have never had any coral burning from adding buffer, Ca or Mg with this method.

[littlesilvermax]

Holy crap!

In all honestly once the corals adapt 1500 shouldn't be too high, but I would try and keep it under 1400. Also too much magnesium at once could introduce a bit of ammonia. I have never measured any, but if you raised your tank by 200 ppm all at once that could end up with big problems. Of course if the damage is already done then do water changes.

Many recommend only raising magnesium by a max of 50 ppm per day. I would suggest 50 ppm per week, to be on the safe side.

Did you try my method of only dosing your newly made up salt water?

Once you get that method figured out it works really really well. Best of all you never dose the tank only newly made up water.

Look at post #2.

[Jaws]

Originally Posted by littlesilvermax

Did you try my method of only dosing your newly made up salt water?

Ya, that's the method I used. My tank is 180G with about 40G in the sump. My Mg was at 1325, which I reached gradually through adding Mg dissolved in top off water and in biweekly water changes. I was doing an 80G water change this time so I mixed the Mg in the fresh water before adding salt until it dissolved. I added the salt, tested and Mg was about 1400. I added the new water to the tank and tested about an hour after and the Mg read 1470. I tested agian tonight and here's what I got:

Mg 1425
Alk 11.5
Ca 420
NO3 0.5
PO4 0

Do you think I still need to do a water change or should I be ok?

[Farrmanchu]

IMO, you should be fine, I just can't figure out where the jump came from.

[littlesilvermax]

Originally Posted by Jaws

Ya, that's the method I used. My tank is 180G with about 40G in the sump. My Mg was at 1325, which I reached gradually through adding Mg dissolved in top off water and in biweekly water changes. I was doing an 80G water change this time so I mixed the Mg in the fresh water before adding salt until it dissolved. I added the salt, tested and Mg was about 1400. I added the new water to the tank and tested about an hour after and the Mg read 1470. I tested agian tonight and here's what I got:

Mg 1425
Alk 11.5
Ca 420
NO3 0.5
PO4 0

Do you think I still need to do a water change or should I be ok?

What salt are you using? IO naturally (at least the 10 or so that I have tested) runs about 1200 so I bump it up to 1380.

Are your corals doing OK now?

[kwirky]

Originally Posted by littlesilvermax

What salt are you using? IO naturally (at least the 10 or so that I have tested) runs about 1200 so I bump it up to 1380.

Are your corals doing OK now?

yeah i use OceanPure, and I gotta be careful, because when I set up my system initially, the Mg was at a skyhigh 1550 or so. Somebody else who uses the same salt gets about 1350 from it, so I think it was the batch.

could be a batch that you got? Did you test it before dosing? I learned from my own experience there that I should test the newly mixed saltwater before I put it in, so I know what to dose safely.

I bought a big thing of magnesium dosing stuff, and I haven't even cracked it open yet because of where the Mg's at.

[littlesilvermax]

Originally Posted by kwirky

yeah i use OceanPure, and I gotta be careful, because when I set up my system initially, the Mg was at a skyhigh 1550 or so. Somebody else who uses the same salt gets about 1350 from it, so I think it was the batch.

could be a batch that you got? Did you test it before dosing? I learned from my own experience there that I should test the newly mixed saltwater before I put it in, so I know what to dose safely.

I bought a big thing of magnesium dosing stuff, and I haven't even cracked it open yet because of where the Mg's at.

Good point! I always test my IO when I get a new batch, to ensure my mixing recipe stays the same.

Also, remember that magnesium (as is alk & calcium) go up proportionally to SG.

[littlesilvermax]

Another thing I though of today regarding magnesium:

I don;t know the chemical reason why, but I have heard before that when you test your water you should wait a day or two for your parameter to settle. Almost like they will not read accurately on a test kit right away. If you are adding something (magnesium, alk, calcium) then you should add some, then test a couple days later and add more.

Perhaps your tank was running higher then your test kits showed, and after a few days they would have showed it. Magnesium will not suddenly increase on its own.