Hanna Magnesium/Calcium meter

[Maivortex]

Any thoughts on this magnesium/calcium meter from Hanna.

HI 93752

Calcium and Magnesium Photometer with 470 nm LED

http://www.hannainst.com/usa/prods2.cfm?id=009002&ProdCode=HI 93752

[tatuvaaj]

Hanna's Ca and Mg reagents don't work in seawater :(

[Boomer]

It is not so much the reagent it is the issue that it does not test high enough.

400 mg/ l Ca++
150 mg /l Mg++

Second, the Magnesium meter will be way off as Calcium can not be any higher than 200 mg / l or it will cause interference and NSW is ~420 mg/ l and NSW is ~1350 mg / l Ca++. And if the Mg++ is over 400 mg/ l there is interference with the Ca++ reading.

HI 93752
http://www.hannainst.com/manuals/manHI_93752.pdf

The HI 93752 meter measures the calcium content in the 0
to 400 mg/L (ppm) range and the magnesium content in
the 0 to 150 mg/L (ppm) range in water and wastewater.

The word Seawater is not there :)

[Maivortex]

The range can be fixed with dilution but if SW is an interference it will never work. Im color blind, I was hoping this would work for SW aquariums. Any other methods available, preferably lab grade tests?

[Boomer]

You can get yourself a Ca++ and Mg++ ISE meter. A pH meter that also has mV on it. Lou's from Pinpoint has a Calcium ISE. You cannot always fix things by dilution all the time you can only go so far. Besides meters are off set by seawater itself, so if the water is diluted it is not seawater anymore and the transfer of the light is not the same as it is not seawater. Not all seawater parameters are affected by this, such as PO4, Iron , copper and Silica. The meters need to be calibrated to a seawater std. This Ca++ and Mg++ is not as easy as it seems, with either a ISE or photometer. You need to really know what you are doing here or get somebody that does. I would not worry about the Mg ++ to much just get it testd by the LFS 1/ m or 2 months

http://www.americanmarineusa.com/