Best way to lower magnesium?
 

I was wondering if there is a better or easier way to lower magnesium other than doing a water change?

I don't see any other option besides water change.

Cheers,
Aquaman

how high is it? and how did it get that high?

Steve

I've heard that kalk dosing precipitates Mg, a bit at a time.

Because of a faulty Salifert Mg test kit, I kept adding Mg over a period of a couple of months. With a new test kit, I realized I had Mg higher than 1500 ppm. It didn't do any harm. I just did regular weekly 15% water changes and let the tank slurp up the extra Mg.

My Mg was up to about 1325 then I did a 40% water change last night. I dosed appropriately but somehow the Mg ended up being about 1470. I'm just worried because it was such a big jump and some of my corals seemed to have the tips burned off and even parts of their sides after I started dosing Mg a month or so ago.

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.

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.

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?

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