# ORP/Redox which values to target for a freshwater tank?



## Gilles (Oct 12, 2007)

Yesterday i installed my ORP sensor, and it was reading 172mv. Today it was reading 163mv. I've read on the internet various values, ranging from "You should have 300mv to 450mv for freshwater" and also "You should have 250mv" Can somebody give some explanation about this?

Thank you,
Gilles


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