PH pen storage question

[George Mc]

Hello, I purchased one of the cheap yellow pH pens from Amazon and also purchased some blue lab storage solution. I purchase the storage solution because somebody mentioned something about storing pens submerged in that solution to keep the tips good. After I read the instructions on the yellow pen it says to dry it off before storage. What do you guys think is best? Get a can of compressed air and blow it off each time or store it in this bluelab storage solution?

 

[Old Salt]

I used one of the low cost pens. It lasted more than a year. This is how I used and kept it:

1. Turn it on and put it into a pH 7.0 buffer;
2. Let the reading stabilize, and calibrate;
3. Rinse with water from the RO, and adjust my nutrient solution;
4. Rinse with water from the RO;
5. Put it into a pH 7.0 buffer until the reading stabilizes; and
6. Cap until needed again.

I use GrowTek's pH Buffer #7 for this. Monthly, I calibrated the pen at pH 4.0, followed by pH 7.0.

 

[Captain Cannabis]

The only time I use storage solution, it's for just that--storage. I'm currently using my pen regularly, so I give it a rinse before putting the cap on, and put the pen in its case.

 

[Old Salt]

The only time I use storage solution, it's for just that--storage. I'm currently using my pen regularly, so I give it a rinse before putting the cap on, and put the pen in its case.

The HM-Digital that I currently use has storage solution in the cap. The low-cost pens don't have the storage solution, and I never used it with them. The pH buffers are calibration solutions. I pour about 1/2 oz into a shot glass for the check, and calibration if required, then discard it. Never put the used solution back in the original container.

 

[George Mc]

It says on the instructions to use distilled water with the calibration powder that I mix in. Is that the same as RO water? Or can I use RO water?

 

[Captain Cannabis]

The HM-Digital that I currently use has storage solution in the cap. The low-cost pens don't have the storage solution, and I never used it with them. The pH buffers are calibration solutions. I pour about 1/2 oz into a shot glass for the check, and calibration if required, then discard it. Never put the used solution back in the original container.

Little OT but, I found with the yellow $15 pens I had to calibrate more often, as they were out. My Apera pen, holds the calibration very well, to the point I calibrate once a month and use the solution weekly to verify it.

 

[Captain Cannabis]

It says on the instructions to use distilled water with the calibration powder that I mix in. Is that the same as RO water? Or can I use RO water?

Ro isn't the same as distilled. Also, I recommend investing in the calibration solutions, they save alot of time.

 

[Gadfly]

Different types of probes have different needs. Some can store dry, some will brake if allowed to dry out. For example, my cheap one clearly states dry storage is fine, but if I owned model X I’d kill the probe.

Distilled is slightly better but RO should be fine as well. Always refer to the manual specific to your make and model.

Reread your post. Use the distilled.

 

[Stunned]

The Apera that I have also has a cap that I fill with Bluelab storage solution.
It says keep the sensor bulb WET
I do, and it's been golden for me for almost a year now
A purchase that I am thankful I made

 

[Old Salt]

The water from a RO/DI is almost identical to distilled water. You can use it if the TDS is less than 20 PPM.
DI = De ionizer, a resin bath (no you can't use rosin ) that removes ions from the water after it has passed through the RO.

 

[Kapncannabis]

So what is the cause for a ph pen to drift out of calibration? I left mine on overnight and it went way out. Heard of people dropping them, that makes sense. Just wondering why the technology requires constant calibration?

 

[Bush Doctor 77]

In order of purity, RO, distilled, DI. De-ionized water has usually been distilled and then run through a resin column to remove any volatiles that carry over with distillation. DI water purity is usually measured in tens of thousands mega ohms resistance if I remember correctly from my lab days.

 

[Old Salt]

So what is the cause for a ph pen to drift out of calibration? I left mine on overnight and it went way out. Heard of people dropping them, that makes sense. Just wondering why the technology requires constant calibration?

Usually it's due to them partially drying out. Another cause is a build-up of salts on the bulbs. I test mine every time before I use it. I use mine every 3-5 days for 3-4 weeks without it requiring re-calibration. I do so whenever it varies more than ± 0.02 from the calibration solution I use.