Testing Magnesium with lower salinity

[gcarcher59]

What effect does low salinity 27ppt for example have on the Salifert Mg test kit? I can't get my level above 1250 and I've added a lot of magnesium over the past week. When I took a small water sample and and raised my salinity to 35ppt I got an elevated reading. I also discovered my refractometer was not calibrated correctly which is why my salt was low to begin with. I am slowly raising my salinity and cut dosing Mg until it's in the 35ppt zone.

 

[blaxsun]

If you're mixing a new batch of salt you're going to have less of everything - including magnesium.

 

[elysics]

What effect does low salinity 27ppt for example have on the Salifert Mg test kit? I can't get my level above 1250 and I've added a lot of magnesium over the past week. When I took a small water sample and and raised my salinity to 35ppt I got an elevated reading. I also discovered my refractometer was not calibrated correctly which is why my salt was low to begin with. I am slowly raising my salinity and cut dosing Mg until it's in the 35ppt zone.

At 35 ppt you got pretty much 30% more salt compared to 27 ppt. That would be 30% more magnesium per water volumme depending on how you raised salinity in the small sample. So from 1250ppm to something in the realm of 1600ppm, does that line up?