pH probes

Steve Burton

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Anyone have any experience with non-Apex probes? I got some used ones with Apex system and modules, one wouldn't hold calibration anymore so I bought a new Apex probe several months ago at a hefty price. The calibration held for a week then shifted, started reading low, so I bought an $8 probe on eBay and calibrated it and re-calibrated the Apex to run together, I'll compare reliability and longevity. So far they seem equal.
Look at this on eBay
https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/112650779679
 

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anit77

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That's pretty interesting. I'd like to hear how it holds up over time.

When I get replacements I buy the BRS double junction ones. That's what's currently running my CARX and I also just bought a spare on sale last week.
 

seand

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I had a cheap one in calcium reactor for over a year with no issues.
 

civics14

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Interesting... but I bought the BRS double junction and been running for 2 years now with no issues. Can't speak for Neptune PH probe though.

Please keep us updated.
 

Onefallleaf

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I haven't used one in an aquarium, but I will say from experience in using one in a lab that the cheap ones are usually just as good as the expensive ones. The calibration will usually hold for 3-6 months and then require ReCal. If you are interested in something further than the first decimal point then the more expensive ones are great, but if not the cheap ones will work. You just need to calibrate it a little more often if your values shift a lot
 

urbanknight

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Thanks for your comment @Onefallleaf. It's getting along time for me to re-calibrate my probes. Like @anit77 , I have been using the BRS double junction ones. I just ordered the cheapo, cited above. I'll check my current one against this new one when I get it and post results.
 

FutureInterest

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I haven't used one in an aquarium, but I will say from experience in using one in a lab that the cheap ones are usually just as good as the expensive ones. The calibration will usually hold for 3-6 months and then require ReCal. If you are interested in something further than the first decimal point then the more expensive ones are great, but if not the cheap ones will work. You just need to calibrate it a little more often if your values shift a lot
Very good information there. I've always bought double junction as well cause that's what people told me to use... :)

Do the expensive ones need to be calibrated less?
 

Onefallleaf

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Very good information there. I've always bought double junction as well cause that's what people told me to use... :)

Do the expensive ones need to be calibrated less?
I'd love to say yes, but thats not true lol. The way those probes are designed, its more accuracy over longevity and durability. Truthfully the probes that they give you in the kits are not really meant to be submerged in water for a long period of time. That can be why they recommend the double junction ones, but honestly it won't help out very much. Without getting into too much specifics, essentially the double junction probes have a safety backup in case the first junction gets fouled or damaged due to measuring at extremely High & Low Temps and pHs (ie. Above 90F, Above 10 pH). This does make the probe last longer overall, but does not mean the calibration will hold. Your calibration gets ruined because of the fouling on the glass because of organics and the water itself. I suggest replacing probes every year or 2 and recalibrating every 3 months or so for utmost accuracy. Before you recalibrate i suggest washing the probe itself with a dilute bleach solution or hydrogen peroxide. BE VERY CAREFUL!! DO NOT LET THE PROBE GET DRY!! Just rinse with RODI before you recalibrate.
 

Onefallleaf

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In short, incase you don't want to read the long reply above, double junction probes are not very useful for our Reef and Aquatic uses. The regular combination or single junction probes are just as accurate. The double junctions last a little longer but real accuracy fades at the same rate as singles. For price, I recommend buying single junction probes.
 

Steve Burton

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I've recently been questioned on what happened with this, guess an update is overdue, but Ph is just not something I worry too much about. Both probes have stayed fairly close until recently, I checked the Apex graphs and the cheap probe readings seem to have dropped significantly,from about 8 to 7.8, starting around August 14. I'll try to get a calibration done soon.
 

huytran91

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That’s interesting. I’ve always had the apex products. I personally feel confident using theirs.
 

myaquariumpro

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I have recently replaced 4 apex probes with amazon cheap ones, not bad. I have to say 3 out of 4 work flawlessly. One of them I couldn’t calibrate accurately. Kept showing .2 -.3 higher than actual ph.

But can’t beat this price
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