Has anyone personally tried this?

[Reggae Fish]

http://www.drsfostersmith.com/Product/Prod_Display.cfm?pcatid=15513&N=2004+113762

 

[sirreal63]

It is for freshwater only

 

[Reggae Fish]

Oops...I can't read but it looked like a neat picture.

 

[chadfarmer]

i have one for phosphate

 

[capncapo]

These guys make a marine version for nitrates. Not cheap.

http://www.americanmarineusa.com/