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Re: low ORP in new tank
> Date: Wed, 16 Aug 2000 10:24:02 -0700
> From: Mark Gilmore <gilmore at physics_ucla.edu>
> Last weekend, I set up a new 75 gal tank (no plants or fish yet). The
> setup is virtually identical to the 60 gal (CO2, pH control). I moved the
> ORP probe from the 60 gal to the 75, and it is measuring approx 220
> My question is: does anyone know why the ORP is so low compared w/ the
> established 60 gal tank? Is this usual for a new tank?
Based on my hazy understanding of ORP...
ORP is measuring the oxidation/reduction potential of the water; it ability to
alter the chemical state of things. Add a strong oxidizer like hydrogen peroxide
or ozone, the ORP goes up and nasty things disappear. Reef people who like
hi-tech use ozonizers and ORP controllers to keep ORP high.
Plain old tap water has an ORP of around 275 mv (at least ours does). In a new
aquarium, there are plenty of things to oxidize and reduce - weird bacteria,
strange stuff on the gravel, etc. It seems reasonable that a newly set up tank
would have lower ORP since the "potential" is being used up to take care of this
> Is this telling me anything important?
"Your ORP meter is doing reasonable things". <g>
George Booth in Ft. Collins, Colorado (booth at frii_com)