Dirtbag
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The difference is we’re using what are likely
very cheap meters compared to your lab quality ones. The manuals of ph meters aimed at dope growers give u no directions for restoring your probe, they just want u to buy a replacement. What’s even more confusing is the difference between what manufacturers recommend for their equipment. Hanna says to never touch the actual probe doing so could ruin it. Bluelab sells a cleaning kit that includes a tooth brush to scrub the probe. Hanna says to store the probe in KCl, bluelab says u can store it in ph4 solution. It’s a little confusing. Over time I notice the probes take a little longer to give a stable reading but eventually give the correct readout. The new probes react instantly. What’s one of your lab grade units cost?
Haha, I've got to add something here. The content of the OP went over my damn head.
I didnt get the bit where he is adding ph down and seeing it rise back up again within minutes....In my reply I didnt mean you cant "adjust" the ph of RO, just that you cant reliably "test" the ph of RO.... good grief. I can see how my reply seemed confusing lol
I agree with some other who said ditch the hanna. Adding ph down will absolutely drop the ph and keep it down, it shouldn't ever drift back up that high naturally. So either your ph down consists of a volatile gas or your meter is playing tricks on you.
I've had the same Bluelab ph pen for I think 3-4 years now? highly recommended. Store it in KCL or ph4 buffer.
Very nice replies, thank you sir. Learned ALOT of stuff that would have taken me a lot of digging and searching- awesome. I’ll most definitely try the pepsin enzymes and windex. I’ve got at least a few old probes I’ll clean up and compare against the new ones and let y’all know the results.They aren't that expensive. I got the most basic unit, I think they're about 80-100€/$ for the whole pH meter todax. A replacement electrode is nearly as much, I think 50-75 depending if it's a gel- or liquid electrolyte electrode. The Electronics are very simple so the box doesn't add much to the price.
Nice thing is you can also take permanent readings with the liquid electrode, you only have to open the refill hole of the electrode and attach a 9V adapter.
Btw. a friend had a Hanna meter and it lasted for ~5 years ('till he broke the glass...) with a couple of cleanings iirc.
When the reading gets inconsistent it doesn't mean the probes gone bad, it's most likely a dirty diaphragm and cleaning can take care of that. Several times actually, as long as you only measure mild solutions as we do!
I would have thought the cheaper meters just copy lab equipment manuals. In the end all of these pH meters work the same.
I'd do it like Greisinger says:
For gel electrodes:
https://www.greisinger.de/files/upload/en/produkte/bda/GPH114_EN.pdf
For liquid electrolyte electrodes:
https://www.greisinger.de/files/upload/en/produkte/bda/GPH014_e.pdf
(Just saw that the EN Manuals are a little different, they advice to just use window/Glas cleaning stuff for "regular" dirt. I'll try it next time my meter won't stay steady. So before you throw a electrode away just put it in some windex or whatever and give it a try.
Btw. you can carefully rub the diaphragm with a paper towel if need be, just never touch the "bulb"!)
And I think pH4 buffer is just (colored) 3mol KCl, that's why it doesn't matter. That's why you always calibrate the meter with it first to its internal reference electrolyte and choose the second calibration point depending on desired pH range and calibrate it second. Not absolutely sure though.
I'm not sure about the CO2 as I saw quite big pH fluctuations in aquariums with heavy CO2 supplementation when there was too much agitation. And ro water could have a lot of CO2, but I would have to read up on gas permeability in ro membranes and am definitely too lazy today. You could very well be right though and it's just the meter having problems with the low ppm solution.
Good to know about pH4/KCl. My Storage solution is empty and I thought of putting it in buffer but will mix a new bottle then. Didn't think of testing the ec.
But now that I think of it it's quite obvious. KCl doesn't give consistent readings, especially nowhere near 4.
Btw. if the probe goes slow change the reference electrolyte if possible. I change it every time I clean the probe.
Ja, you normally don't need to, I just made it part of my yearly maintenance. And the Greisinger electrodes have a poorly covered port for refills and pressure equalisation when you do long term measurements, so there's always a little cristalisation and loss of electrolyte. Proven but not the best design I could think of...
Over here it's a real pain to find unscented scrub stuff (what's it called in English?) like bluelab advises, so I just used very fine grit sandpaper to clean my truncheon meter.
Is the ceramabrite scented?
And has the normal BL tds meter graphite electrodes like the truncheon?
Holds up just fine too, except the battery cap getting strange cracks. May be cause I used it to beat an ass**** that wouldn't want to leave my home a couple years ago. Multifunctional ;)
PH of RO water
Neutral pH is defined as 7.00, but RO water typically shows a pH of between 5.00 and 6.00. .....Given that the pH scale, like the Richter scale for earthquakes, is logarithmic, that means that pH 5.00 water is actually 100 times as acidic as pH 7.00 water.
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