View Full Version : my ORP is 920

12/09/2010, 07:08 PM
I have been monitering my orp for about 2 years now, I have never seen it reach 400 until a few days ago. I upgraded from a neptune aqua controller III to an Apex. When I changed to the Aex the orp probe was reading the same as it was with the old controller, 350. It stayed there for a couple of days, give or take maybee 30. Then it started consitantly rising. I have the Apex controlling an ozinizer. When it reached 450 I disconected the ozinizer just to make sure. 3 days later my orp is at 920. I checked the probe with a new packet of calibration solution. The solution was 400, the probe read 398.
I started using brightwell aquatics salt just before the orp started rising. I used to use cheaper salt mixes. I checked the orp of the newly made salt mix after a day or so of mixing, it read 328. I also changed my carbon just before the orp started rising. The sarbon was a new container of Bulkreefsupply ROX carbon. I have been using this carbon for a couple of years now, the same amount, changed about once every month.
Any ideas???

12/09/2010, 07:09 PM
Oh yeah, all coral and fish look fine.

12/09/2010, 09:47 PM
Probe bad or the probe has algae on it which raises the ORP. No such thing as 920 mV as all would be dead ;) Sounds more like a probe issue, wires bad, connection, stray voltage leak, etc..

12/10/2010, 05:43 AM
Exactly what boomer said.

Plus, check the probe and how it mounted. Some have gel salt bridges and are sensitive to mounting angles. A slow constant change can sometimes be the salt bridge failing.

12/10/2010, 04:16 PM
Thanks, I am having some other problems with the new Apex, I am going to send it back to Neptune Monday for them to fix it.
What had me curious is when I put the probe in the calibration solution it read 398, the solution was 400. Also when I tested newly made salt water it read 328, which seemed logical. I don't know why I am only getting faulty readings with my aquarium water...