How often do you calibrate your PH meter?

Hackerman

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I am new to PH so bare with me, please.

I bought this one...

http://www.ebay.com/itm/Milwaukee-p...052?pt=LH_DefaultDomain_0&hash=item19eae0e2bc

I calibrated it yesterday to 7.0 as instructed. I tested my input water and the calibration solution back and forth to make sure it was consistent.

I store it in a jar of Deer Park Spring Water at about 6.8PH.

This morning, I checked my run off and it was 6.2PH. When I put the meter back into the spring water, I noticed it was reading 6.2 and didn't change.

I put it in the calibration fluid and it went to 6.1. So, I re-calibrated to 7.0 and put it back into the Spring water. It went to 6.8 (like yesterday) and stabilized.

Should I re-calibrate every day? How long does the calibration solution keep a 7.0?

Thanks

View attachment $_57.jpg
 
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I went through 2 of those same ph pens before I got one with the replaceable probe. I calibrate my meter every 2 weeks. I don't leave my probe sitting in spring water though, I have always just dipped my probe in regular water, wiped it off a bit gently and then put the probe cap in the probe.
 

Hackerman

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Don't you have to store them in water to keep the tip wet?
 

Hackerman

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How do you leave the tip wet without storing it in water? They dry up pretty fast.
 
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Mine sure doesn't. The cap that goes on mine keeps it moist. I use mine every day though. It never sits for days on end without being used.
Looks like storing it in deionised or distilled water is no good. Not sure about Spring water though. This is what Wiki says:

When not in use, the glass probe tip must be kept wet at all times to avoid the pH sensing membrane dehydration and the subsequent dysfunction of the electrode.

A glass electrode alone without combined reference electrode is typically stored immersed in an acidic solution of around pH 3.0. In an emergency, acidified tap water can be used, but distilled or deionised water must never be used for longer-term probe storage as the relatively ionless water "sucks" ions out of the probe membrane through diffusion, which degrades it.

Combined electrodes (glass membrane + reference electrode) are better stored immersed in the bridge electrolyte (often KCl 3 M) to avoid the diffusion of the electrolyte (KCl) out of the liquid junction.
 

Hackerman

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Thanks. I'll keep reading and see what I come up with.

:)
 

Hackerman

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I went down today and the test probe was sitting in the Deer Park 6.8PH water and it was reading 6.2. I put it in the calibration solution (7.01PH) and it went to 6.3.

I calibrated it back to 7.0 and measured the Deer Park. Measured 6.8 OK, cool.

I watered my plant and captured the run off. It measured 6.4.

Maybe I should get a better quality tester. I read about a lot of people who used this model and liked it.

I'll keep on it and see what happens.

Maybe I am not waiting long enough for the meter to adjust and read. I give it a minute or so in the solution before I calibrate it. That's more than enough, isn't it?
 

MR1

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Hackerman , I have used the cheaper models but they took to long to stabilize and did not last long . My last one cost aroun $50 and is worth every penny . I calibrate maybe once every 2 weeks. never replaced probe and I have had it for many years. I has a stabil reading in about 5 seconds sometimes less. There is a little piece of foam in the cap to keep it wet, I just use ordinary tap water.
 

MR1

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Hang on I will give you a link. I also have their TDS meter with same results.

[ame="http://www.amazon.com/HMDPHM80-Digital-pH-Temperature-Meter/dp/B0096N8OWI/ref=sr_1_1?ie=UTF8&qid=1403566797&sr=8-1&keywords=HM+digital+ph80"]http://www.amazon.com/HMDPHM80-Digital-pH-Temperature-Meter/dp/B0096N8OWI/ref=sr_1_1?ie=UTF8&qid=1403566797&sr=8-1&keywords=HM+digital+ph80[/ame]
 
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I went down today and the test probe was sitting in the Deer Park 6.8PH water and it was reading 6.2. I put it in the calibration solution (7.01PH) and it went to 6.3.

I calibrated it back to 7.0 and measured the Deer Park. Measured 6.8 OK, cool.

I watered my plant and captured the run off. It measured 6.4.

Maybe I should get a better quality tester. I read about a lot of people who used this model and liked it.

I'll keep on it and see what happens.

Maybe I am not waiting long enough for the meter to adjust and read. I give it a minute or so in the solution before I calibrate it. That's more than enough, isn't it?
I usually dangle my probe into the liquid, stir the liquid a bit, walk away and do something else for 2-3 minutes and then come back and stir again till the number doesn't move. I use ph up and down to go from there.

For the record, I don't believe in ph your run off. I have seen to many people drive themselves crazy trying to get their run off to fall in the 6.3-6.8 range. They would raise the ph of their water and feed higher and wind up doing damage to their plants in the long run. I use a neutral soil with sweet lime and ph everything to 6.5. I don't care if my run off says 9...so long as my plants look good. jmo
 
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Hackerman

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Thanks again, I'll try that, too.

I have been growing since the 60's and this the first time I have ever PH'd anything. LOL How important can it be?

Still, these hybrid plants sure seem to be more sensitive to stuff like PH than my old bag seed grows. So.... I'll PH from now on. LOL
 

Hackerman

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I picked up an HM Digital PH80 yesterday and it seems to be more consistent than the Milwaukee.

The water I am using (and have been using for decades) is measuring 8 and sometimes up to 8.5. I have not checked it yet with nutes in it.

I am continuing to use Deer Park for my 2 mothers but I can't dump 4 gallons every 2 days that I need for the flowering room. LOL

I just read someone say that household items are not great to use and I also read that the PH up and down that you buy isn't especially good for the plants.

I do need to find a solution for this. I think 8+ PH is too high.
 
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Items like lemon juice and vinegar etc, are not good to use. They don't hold the ph for very long and I wouldn't want to give crap like that to my plants. Ph up and down from General Hydroponics is really good and you can even get it on Amazon. I buy the powder and then mix up a bottle of up and a bottle of down with tap water. Been using it for years now.
 

Hackerman

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I will check and see what the local store carries. Thanks
 

jingo

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Here's the meter I use I calibrated it once 2 months ago and it stays on. It floats which is real handy. Oakton EcoTestr pH 2 Waterproof pH Tester, 0.0 to 14.0 pH Range Oakton [ame]http://www.amazon.com/dp/B004G8PWAU/ref=cm_sw_r_udp_awd_XyJRtb1K02W56[/ame]
 

trillions of atoms

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Every week for me.... mine has a sponge that soaks the water in it without pooling.
 
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