Did RODI water ruin my PH probe?

Johnson556 · May 21, 2018

Recently my ATO broke so I've been adding a pitcher of water anytime I can to top off the sump.

However, yesterday I dumped about a gallon into my sump where my PH & ORP Probe is. I usually slowly pour it into the return pump chamber. As I'm driving to my friends house 20 minutes later, I start getting all these texts/notificatons from my Apex saying my PH is >8.4, then 8.5 and all the way to 8.88 at it's highest.

Two hours later I get home and test the PH with a Salifert kit that read 8.15. Clearly something funky happened with my probe and the RODI. Did I just destroy this probe or can a re-calibration fix this?

Probe is 5 months old, Tank is a Marineland 180, Sump is about 50 gallons

redfishbluefish · May 21, 2018

pH probes can NOT be submerged. If it was submerged, it's most likely shot. I'd soak it in vinegar overnight, rinse and recalibrate, and see what you have.

And FYI, RO/DI on the probe end will not ruin the probe.

Dr. Reef · May 21, 2018

probably due for a calibration if has not been done in last 5 months.

Johnson556 · May 21, 2018

Thank You

Randy Holmes-Farley · May 21, 2018

DI water exposure is not a problem for probes. You shouldn't store them in it because internal salts will slowly leak out, but rinsing is fine. and nothing happened in tank water with DI added nearby.

Randy Holmes-Farley · May 21, 2018

Probe submersion depends on the design. A sealed probe can be submerged, and even one with a fill port can be short term if the hole is properly covered.

Johnson556 · May 21, 2018

The probe is a Neptune lab grade probe, standard red one

Randy Holmes-Farley · May 21, 2018

Johnson556 said:
The probe is a Neptune lab grade probe, standard red one

I've never seen it. Is it refillable? Meaning it has a hole in the upper part of the body. Many hobby probes do not.

http://www.courage-khazaka.de/index.php/en/faq-en/faq-scientific-devices/72-skinphmeter

LobsterOfJustice · May 21, 2018

Maybe a bubble got trapped on the probe tip when you poured water directly into the compartment?

Stigigemla · May 23, 2018

A normal pH probe does not work in RODI water. It is not enough iones there. There are special probes for very weak solutions.
My RODI water is normally about 1 microsiemens /cm but after a week in a bucket it is 5 because it has been an uptake of CO2 from the air.
If you have a very good meter and very good RODI water in an extremely clean container i would suspect your pH to go down to about 5,5 in a day or 2.

kodo28 · Jul 6, 2019

Randy Holmes-Farley said:
DI water exposure is not a problem for probes. You shouldn't store them in it because internal salts will slowly leak out, but rinsing is fine. and nothing happened in tank water with DI added nearby.

Hi Randy there is any info about the time when ions would start to leak out and have an impact on the accuracy of the probe ?
Would you say that keeping for example 2 hours the probe in RODI water wont have any bad effect on the probe

Randy Holmes-Farley · Jul 6, 2019

kodo28 said:
Hi Randy there is any info about the time when ions would start to leak out and have an impact on the accuracy of the probe ?
Would you say that keeping for example 2 hours the probe in RODI water wont have any bad effect on the probe

2 h is not a problem. The ion diffusion is a slow process. Just allow it to re-equilibrate in buffer or tank water for a few h.