new ORP/PH controller - low ORP readings???

P

psteeleb

Premium Member
I just hooked up a new ORP/PH controller and my ORP readings are surprisingly low - in the 175 range. Everything in the tank is healthy so I'm not sure if I should trust the meter/controller or not. Do these things need calibration or is there some break-in period? Or, does anyone have any other experience with low readings like this?

The meter controller is a Milwaukee SMS125 ORP/PH controller

the manual only indicates calibrating the PH probe.

Pete
 
There could be lots of reasons why your ORP is low. A lot of people run ozone on their systems to compensate. To better understand ORP read this
http://www.reefkeeping.com/issues/2003-12/rhf/feature/index.php
 
Some ORP probes can be calibrated. One problem with ORP probes, though, is that they seem to 'remember' their last reading for a while. It can take a day or so for it to stabilize after moving from one solution to another.

(I think that's mentioned in the RFH article linked above by Les.)
 
Mine has taken over 1 month to finally stabilize to what I consider 'correct' readings, although I'm not sure it's not related to something else at the moment. However, Randy Holmes-Farley has 3 months of newer ozone/orp info at the following reefkeeping.com months/articles:

http://www.reefkeeping.com/issues/2006-03/rhf/index.php
http://www.reefkeeping.com/issues/2006-04/rhf/index.php
http://www.reefkeeping.com/issues/2006-05/rhf/index.php

He discussed the 'memory' effect that seems to occur in Orb probes/readings a bit (i think in 2006-04 - part 2). And just has some good allround info on the setups/reading he tried. Good reading HTH

Doug
 
thanks for the links - very informative
as for the ORP - it was up over 60 points today when I came home from work, so I'm sure it just needs to settle in for a few days before I can trust any readings

thanks

Pete
 
You would be right about it taking a few days to move to the correct reading. And they also have to be kept pretty clean. I scrub off mine with a toothbrush every few weeks.
 
It took over three months for my orp to stablize to 375. So dont feel bad. I have the Red Sea Ozonizer with a built in controller. So i dont really get to calibrate.
 
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