How about an article on refractometers?

[BORECKI]

Randy;
I read your article on salinaty with great interest and found it enlightning. But there is a growing trend amoung aquarists (yours truly included) to use refractometers in place of swing arms or floats.
Would it be possable to do a follow up article aimed at that segment of the hobby as far as use and maintenence is concerened?
Boris.

 

[randy holmes-farley]

Boris:

That's a good idea!

Here's one that's already done on conductivity. I prefer conductivity to refractometers, but both work very well.

http://www.animalnetwork.com/fish/library/articleview2.asp?Section=&RecordNo=1300

[ February 11, 2002: Message edited by: Randy Holmes-Farley ]

[ April 19, 2002: Message edited by: Randy Holmes-Farley ]</p>

 

[95galReef]

Randy,

So can I use my Hanna TDS Meter to measure my salinity? what would the conversion be from PPM to PPT ? I read on another post that someone used a refractometer which put the salintiy at 1.025 and then put the TDS in the same water and it read about 457ppm. Does this sound about right?

-Tom-

 

[randy holmes-farley]

So can I use my Hanna TDS Meter to measure my salinity?

If it covers the appropriate range.
Many do not.

1 ppt (part per thousand) = 1000 ppm (parts per million)

Natural seawater with a sg of about 1.026 has S=35, or about 35 ppt (35,000 ppm). The unit that reads 457 ppm must be maxed out, and cannot read the higher ranges properly.

HOWEVER, there are a number of different ppt scales, which really screws things up calibration for use in seawater.