low magnesium

[jjoos99]

what will low magnesium cause? I have been seeing loss of color and some stn over the last month or so. I tested with a different test kit today for mag and it showed that I was only at 980. I can understand it will effect growth but was wondering about anything else?
thanks
Jeff

 

[Wiskey]

I've never seen that much effect, but it's never been that low for me. If I were you, I would raise it to 1300 or so. It can't hurt.

Whiskey

 

[Reefvet]

I tested with a different test kit today for mag and it showed that I was only at 980.

You mean you got a lower reading than you did with another kit as your reference or you simply got a lower number after switching brands of test kit ?

The biggest potential for error in any test kit is human error. Was this the first time you used this kit ?

980 is also well within the typical 20% error of hobbyist level test kits.

Irregardless of your answers to my questions you can raise the Mg level by 100 ppm a day without stressing your corals.

 

[downbeach]

Getting a second opinion on the test is a good idea. What is your SG? What do you use to measure it with? If its a swing arm type hydrometer, or some other device that needs calibration, it may be leading you to add too little salt mix to your make up water, which by extension will be adding too little Ca, Mg and Alk as well. Low Mg will cause your Ca and Alk to precipitate out of solution, making them unavailable for your animals.

 

[jjoos99]

I recently got the local clubs test kits and tested after getting my results back from aqua medic. The results from their tests show my potassium clear down to 140 but my mag was good at 1250. Using my salifert and the clubs salifert I am getting 1050 and 1080 today after dosing some mag last night. My potassium with a red sea kit is reading 320. My plan is to keep adding 1000ml of brs mag supplement per day till i reach 1350 or so. Using their calculator I need to add little over 6000ml to reach 1350.
downbeach.
I did recently have my salinity too high in the tank. Close to 1.03 I had never calibrated my refractometer, ordered some calibration fluid and have that issue corrected. I havent seen much change in my corals is why I am still guessing what might be going on.
thanks
Jeff

 

[rt67ghy]

Low Mg will cause your Ca and Alk to precipitate out of solution, making them unavailable for your animals.

+1

Low magnesium means there'll be less calcium available for your corals to build their skeleton and if it's very low below 800ppm it will lower the pH. Keeping Mg in the range 1250-1350ppm should be fine.