Magnesium Problem?

aaronlp · Jan 4, 2013

Ive been testing my 75 gallon(mostly filled with sps frags and maybe a few small colonies)

And everyday i test the mag it is 1200ppm, i add 100ml a day and there really isnt much change in between days...

Alk has been staying around 9.8dkh and Calcium 500ppm

Any idead to why the mag isnt moving around much?

Been testing for a about a week/ Around 15 frags 3 small colonies and chalices in the tank

Using BRS Dosing Products

Sahin · Jan 4, 2013

Providing your test kit is ok, this is the effect I had when my tank was new. Now that it is over 3 months old, the mg requirement has slowed a little. Growth of various organisms and corraline etc is probably cause. Just to be on the safe side, have your mg level measured by someone else etc.

Isoprene · Jan 4, 2013

+1 to the above, test it against something else. DON'T dose too much all at once, do weekly doses increasing each time. If your dosing daily trying to raise it its going to tank your alkalinity (these things tend to fight with one another) so watch your alkalinity big time. I dropped mine a whole point by doing a water change and measured out 2x my Mg dose by accident. Be careful is my best advice test often and make sure your testing equipment is matching up with someone else readings / LFS readings. A bad test kit can mean total information failure and over / under dosing problems. Also dosing daily does not always give accurate reading (dosing then testing right away) dose once and give it 3 to 4 days before testing to see the effects.

Im new to the sps too but I have had the same exact problems in the beginning. I caught my alkalinity drop in time, just be careful.

shellynjason · Feb 19, 2013

What are you using to get 100ml mag added per day. I use B-ionic mag and it states to only go 15ml a day so salinty doesn't raise to much, my mag is pretty low and was hoping to go more then 15ml a day.

Chameleon · Feb 21, 2013

It takes a lot of mag to make it budge on the test kit. But like others mentioned I'd stop the dosing until you see it decrease for now. I'd be more concerned with a calcium of 500 then mag 1200. 1200 is a bit low but that high calcium level could be contributing to your issues bringing mg in balance. When calcium drops to the 380-440 range then I think is the best time to focus on Mag levels.

Downbeach · Feb 21, 2013

What kind of salt mix are you using? If it's not a "reef" type, i.e. Reef Crystals, its going to have lower levels of Ca, Mg and Alk.
What is your salinity? If you mix your SW on the lower end, your Ca, Mg and Alk will be on the low side too.
What do you use to measure your salinity? If it's a swing arm type of hydrometer, it may be giving you erroneous readings, and you may not be adding enough salt mix to your make up water. If you use a refractometer, or meter, is it calibrated? An uncalibrated device will give you bad information too.
What are you using to test your Ca, Mg and Alk with? Did you check these readings in your make up water too?
It would be better if your Mg were a little higher, but 1200 isn't all that bad. According to the BRS calculator to get your Mg from 1200 to 1350, you would need to add about one quart(32oz.) of their solution. So, if you added about 2 oz. a day for 16 days you should get to 1350. and stay within the 100 ppm per day threshold.

Davinci · Feb 22, 2013

I think you should use another test kit. I think its really hard to have calcium at 500 with 1200 mag. I am pretty sure you are getting a false reading.