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View Full Version : Neptune Lab-Grade PH probe longevity?


BlackTip
06/03/2016, 08:22 AM
How long does it last?


I have a lab-grade Neptune probe that is less than 8 month in use, well maintained and cleaned regularly. It started drifting downward dramatically. It used to read 8.2, now it reads 7.9. My alkalinity is 9.0 dkh, fresh air line to the skimmer, and I dose kalk in ATO.

My newer lab-grade probe that I bought for the calcium reactor reads .2 higher, when I put it in the DT.

I calibrated it 3 times with Milwaukee 7.0 & 10.0. I talked to Netptune tech support and they didn't offer any solution or explanation.

I am ****ed, because it didn't last very long at all. I expected years of service for $75 probe.

zsuman101
06/03/2016, 05:53 PM
probes don't last for yrs unfortunately, 1 to 1.5 yrs tops ime

slief
06/03/2016, 06:02 PM
How long does it last?


I have a lab-grade Neptune probe that is less than 8 month in use, well maintained and cleaned regularly. It started drifting downward dramatically. It used to read 8.2, now it reads 7.9. My alkalinity is 9.0 dkh, fresh air line to the skimmer, and I dose kalk in ATO.

My newer lab-grade probe that I bought for the calcium reactor reads .2 higher, when I put it in the DT.

I calibrated it 3 times with Milwaukee 7.0 & 10.0. I talked to Netptune tech support and they didn't offer any solution or explanation.

I am ****ed, because it didn't last very long at all. I expected years of service for $75 probe.

I get many years from my Neptune probes. I clean them with a soft tooth brush every so often. They are in a dark spot in my sump with high flow and no microbubbles. I'd bet your probe is just find and this is more of an issue with probe placement or your calibration practices.

As for the probe from your reactor reading .2 higher than the tank probe, that should be expected if you calibrated it properly. A calcium reactor probe should be calibrated with pH 4 and pH 7 solution so it's accurate at calcium reactor ranges. It will be less accurate above the high calibration points. If you calibrated the reactor probe in 7 & 10 solution, you likely aren't getting good reading on your reactor pH. The tank pH probe should be calibrated in 7 & 10 solution as you did.

Have you taken the tank probe out and tested it in calibration solution to see what it's reading when placed in calibration solution? How long are you letting the probe settle during calibration? I usually let it settle for up to 10 minutes per solution and swirl the probe a bit while it's in the solution. I also take the packet and let it sit in tank water so the calibration solution matches the tank temp. I then place the packet in a cup of tank water which I sit in the sump. That way the solution remains at tank temp. I do this so the temp compensation matches. Otherwise, if the solution is at a different temp than the tank, the temp compensation will be off. Even a couple degree difference between calibration solution and tank temp where the temp probe is can result in a deviation of .2 pH or more. Just pull up your pH graphs and overlay temp on the graph and you will see that pH swings tend to follow temperature swings.

Jyetman
06/03/2016, 09:07 PM
My Apex lab grade turned 2 years Feb '16