False orp reading?

[Joshua1023]

My ozonizer has been reading the orp at over 350 for the last week or so. Its not even running so I thought this reading would be impossible. Is there any way to make sure that the reading I'm getting is accurate. A homemade calibration solution would be nice. I'd buy one if I had to.

 

[Habib]

Pinpoint by American marine has an ORP calibration solution.

FWIW, ORP probes can get contaminated with a layer and might require cleaing.

 

[Joshua1023]

What is the best way to clean it. Just stick it in some vinegar for a bit?

 

[bertoni]

I'd try the ORP calibration fluid. For cleaning, does the manufacturer give any instructions? What brand is the probe?

That ORP doesn't sound all that unreasonable, off-hand, but I don't run ozone, personally, and don't measure ORP.

 

[Joshua1023]

It has just sort of changed by itself is all. When I first set up the ozonizer the reading was about 260. I slowly raised it and was told that I won't want to go over 350 because that could be bad news for my corals. I took it out and cleaned it w/ warm water and then dipped it in ro/di. I got the same readings when I plugged it back in. The probe itself is an American Marine.

 

[WaterKeeper]

An easy method to clean one is to soak it in staight bleach solution overnight. The next day, rinse and clean it with a 50/50 vinegar solution for a couple of hours, Again rinse , soak in some RO/DI for a few hours and put it back into use.

Do that only for the probe, as soaking the meter itself, can cause problems.

 

[DrBDC]

I'm not sure calibration of ORP probes helps much due to the constant cleaning to bring the readings back down. If you calibrate it, it will be off the next day or at least w/in a week. It seems better to just use it as a guidline vs. an exact measurement. It will creep up a couple weeks after cleaning. Most seem to use 400 as a setpoint vs. 350 but there's nothing wrong with 350 either. I've even seen some use 450.

I use vinegar on mine. I let it soak about 30-45 minutes, then gently toothbrush the end, swish it in the vinegar, then swish it real good in some regular water or container of water from the tank to rinse the vinegar off. Then it takes a day or three to get back to a somewhat normal reading.

 

[Joshua1023]

Waterkeeper, DrBDC, thanx for the first hand experience. I appreciate your responses.