Magnesium problems

jgraz · Apr 10, 2012

Well I have trying to get my parameters in check for about 2 weeks now. I have been dosing 2 part to get my numbers up to par and was running into problems. Calcium always went in without a problem. Whenever I dose the alkalinity part it would almost instantly precipitate. It has never done this with me in the past. I usually give at least five min between parts. Anyway I have noticed that neither my cal or alk have increased. So I checked my mag, with salifert kit five days ago. It was 1250. So I decided to start dosing that. I have been dosing 15-20ml per day since then. Two days ago my mag tested at 1170, and this morning it was 1100. WTF is going on. I decided to check my make up water and it also tested low, 1150. I keep my water mixing and use some and replace as needed. So I always have saltwater avail. Just for info here ate my other parameters:
Am-0
No2-0
No3-0
Ph-8
Alk-7
Cal-400
Mag-1100
Phos-.06(Hanna)

Anyone got any idea about what's going on here.?

downbeach · Apr 10, 2012

jgraz said:
Well I have trying to get my parameters in check for about 2 weeks now. I have been dosing 2 part to get my numbers up to par and was running into problems. Calcium always went in without a problem. Whenever I dose the alkalinity part it would almost instantly precipitate. It has never done this with me in the past. I usually give at least five min between parts. Anyway I have noticed that neither my cal or alk have increased. So I checked my mag, with salifert kit five days ago. It was 1250. So I decided to start dosing that. I have been dosing 15-20ml per day since then. Two days ago my mag tested at 1170, and this morning it was 1100. WTF is going on. I decided to check my make up water and it also tested low, 1150. I keep my water mixing and use some and replace as needed. So I always have saltwater avail. Just for info here ate my other parameters:
Am-0
No2-0
No3-0
Ph-8
Alk-7
Cal-400
Mag-1100
Phos-.06(Hanna)

Anyone got any idea about what's going on here.?

Although 1350 is supposed to be the ideal level for Mg, the rule of thumb is it should be about 3 x your Ca reading, so if your Ca is 400, a reading of 1200 would be an acceptable amount. If I were you I'd get a second opinion. Try a different Mg test kit, and/or have another reefer check your Ca, Mg and Alk.

sjfishguy · Apr 11, 2012

What Jim said. Also, what is your salinity and how are you measuring it? Make sure you refractometer is calibrated properly. If your salinity is not what you think it is, all the kits and tests are worthless. Stuff should not be precipitating at those numbers.

jgraz · Apr 11, 2012

I keep salinity at 1.025. Measured with a refractometer, though I have been calibrating with rodi and have recently found that its not a good idea to do that. My other tank is fine. Im gonna try to get some calibrating fluid this weekend.

sjfishguy · Apr 12, 2012

There ya go. I think you are gonna be very surprised when after you calibrate with the solution.

NJ Reef Farm · Apr 13, 2012

hey my stuff is all calibrated if you want to stop by and set yours up to match

jgraz · Apr 13, 2012

NJ Reef Farm said:
hey my stuff is all calibrated if you want to stop by and set yours up to match

Ill let you know. Im gonna try to find some calibration fluid this weekend. I also may just buy a new refractometer since the one im using does not have auto temp compensation, so i've come to find out.

jgraz · Apr 16, 2012

Well just an update. I checked my refractometer and all is good. I got a tip to check my salinity before topping off with fresh. our thoughts were that my salinity was going to high after evaporation and inturn causing some other problems Ive been encountering. Let me start by saying that I very rarely check my salinity in my tank and normally only check my make-up water to match what I "knew" my tank was. Boy, was I wrong. Last night before topping off with fresh I checked my salinity and found that it was only 1.023. So after topping off a 1/2 gal of fresh my salinity was probably dropping dramatically. I didn't bother to top off with fresh instead I used some saltwater I had mixing to beging raising the salinity slowly. I guess I'll be checking more regulary after this mishap. Lessons learned I guess.