wts : American Pinpoint ORP controller

[Fragmaster]

Used for about 10 months ( So should still be under warranty)

Bought from reef depot

Can measure negative orp readings too so can be used to tell the orp in a de nitrator.

Bought at $300 plus ( selling for $240 )

[acontia]

i don't think it can measure negative levels.....

[Fragmaster]

i don't think it can measure negative levels.....

http://www.americanmarineusa.com/orpcontroller.html

ORP Measurement Range –1,999 to +1,999 mV

Bro, i suggest you can read up before you comment .