calibrating PH meter

[mysticls]

i got my new hannah ph/ecs/temp meter.. do i need to calibrate it now or can i wait? its my understanding it comes calibrated from factory.. how often should i recalibrate it and what buffer solution should i get out of the 3 they offer?

 

[Guest]

I would HIGHLY recommend you calibrate it. After paying the cash for the meter I dont see why ya wouldnt want to double check it for accuracy.

The buffer solution can be purchased from the same vendor ya bought the pen/monitor from. Each meter has a specific need for the solution's ppm so read the manual and make sure you get the right stuff! 7.0 and 4.0 solutions (if yours is a dual calibrating pen).

Now depending on your meter type your cleaning schedule might be diff. For a meter that sits in the solution 24hrs a day (constant monitoring) I'd recommend cleaning and calibrating once a month.

If yours is a stick meter that you just dip and rinse I'd recommend cleaning/calibrating once every 3 months.

Following the above, including the cleaning (very important part), you can easily expect your pH meter to last quite a few years! Without it, and you'll be like most, having to replace the probe once a year.

 

[SmokeRings]

hmm... i havent calibrated my ph meter, I usually just test distilled water from time to time and if the reading is reasonably close to 7, I assume its ok (since Im not inclined to be anal over .2 or .3 pH accuracy... then again I mainly use the ph meter to get an estimate of where my soil PH is)

im gonna calibrate it soon though

 

[mysticls]

thanks

 

[clowntown]

hmm... i havent calibrated my ph meter, I usually just test distilled water from time to time and if the reading is reasonably close to 7, I assume its ok (since Im not inclined to be anal over .2 or .3 pH accuracy... then again I mainly use the ph meter to get an estimate of where my soil PH is)

im gonna calibrate it soon though

Almost every brand of distilled water that I've purchased reads different, but none read 7. Most were sub-6, as low as 4.5-ish. I thought this was odd, since theorhetically distilled water should be a perfect 7.0. After a little research I found that it's rarely the case as CO2 from the atmosphere easily dissolves into the water during the distillation process, lowering the pH.

Most purified water that I've purchased, on the other hand, almost always reads at 7.

The very minimum you should be getting is the 7.01 calibration / storage solution. It's very important that you do not let the electrode dry out. It seems to be a very common mistake to store it dry, which will almost always ruin the electrode in a short period of time.

If it has a dual-point calibration system (typically 4.01 and 7.01), you could optionally get a 4.01 solution for better accuracy. My Hanna pen has two adjustable dials for calibrating @ 7.01 and @ 4.01, but the 7.01 dial can also calibrate @ 10.01. I'm not going to buy a 10.01 solution, though. I calibrate roughly once a month.

 

[Guest]

Yea, personally I dont see why someone would pay the $$ for a meter but not want to spend the extra couple of dollars for cleaning/calibrating solution.

After all, there's nothing worse than KNOWING your pH is right on, but it's far from due to an uncalibrated meter.

 

[farmerbill9]

if you got a college nearby the chemistry department probably wont mind calibrating for you ( mine didnt). you do want to calibrate it out of the box. mine also said it was pre calibrated, IT WAS NOT! once i got it calibrated it didnt wander at all in 6 months. (but now that i mention it ill check it tonight and let you know)

1 point in ph difference is a 10x difference
6.0 to 7.0 is a 10 times difference !!!
6.0 to 8.0 is a 100 times difference !!!!!!!
you see how you need to be SPOT ON with your ph

do your self and your plants a favor get calibration fluid !!!

 

[farmerbill9]

i checked my pen and i was off +0.25 after about 3 months. thanks for reminding me to check my pen !!

 

[clowntown]

A big trend / problem that I've noticed is that those who don't own calibration solution, and thus don't calibrate, also store their electrodes dry. If anything, store it in some clean purified (RO or otherwise) water... but never dry.

 

[mysticls]

what do you mean about not letting the electrodes dry out?? i am assuming the electrodes are whats in the end of the pen??

here is the meter i have

http://www.sunstoneherbals.com/hanna_combo_ph_ec_tds_temp_waterproof_tester_hi98129.htm

so your saying i should keep the tip of my pen in a glass of RO water??

 

[Ono Nadagin]

in the cap of the 98129 ther eis a small sponge(if it isnt there it should be).. you keep that sponge in the side of the cap that the electrode fits in and you keep it moist with storage solution, so when you put the cap on the pen it 'stores' the electrode in storage solution... not in RO water

I also recomend you do a 'dual' two point calibration every two months, it is how often I was told to calibrate my 98129... and it has lasted 7yrs

 

[mysticls]

well i dont have any storage solution.. i've got RO water for now, will that work?

guess ill have to buy some calibration solution, ph4.01, ph7.01, and some storage solution

 

[clowntown]

For now, if you DON'T have storage solution then yes plain water will be far, far better than dry. But if it's been stored dry for any period of time, I highly suggest you test / calibrate it since the chances of it being off (or permanently damaged goods) are quite high.

 

[mysticls]

well its still brand new in the box.. havent used it yet

where can i buy storage solution?? i'm gonna order some 4.01 and 7.01 calibration solution from my vendor.. if i ask for storage solution he will know what im talking about??

thanks for the help

 

[clowntown]

7.01 calibration solution doubles as a storage solution. You can get it anywhere you can get a pH meter.

 

[Ono Nadagin]

the strage solution and PH calibration fluids dont come in pouches and bottles.. I bought the bottles and then bought myself eye dropper lids for those bottles.(about $1 each)to dispense them for use... you should store them in the fridge if you can. Also always use a plastics container of some sort to do the calibration in, as glass and metal containers can through the calibration off...

 

[mysticls]

how long does a pack of calibration solution work for?? can i use the 7.01 solution to calibrate my pen and to also store it??

ONO, how important is it to store in the refrigerator?? planned on storing this with all my nutrients, etc which is kept at 73-78 degrees

 

[jcsmooth]

Mysticls....calibrate your pen while it's dipped into it's cap, then just leave it in there. When you take it back out again and after you've used the pen to check some water, rinse it with the liquid that is in the cap. Refill the cap, start all over again.

I suppose it depends on what pen you have, but assuming you have a cap, this should work out dandy for you.

G'luck,
JC

 

[mysticls]

so when the solution comes, its in a bigger bottle that can be used more than once? i was under the assumption it was used once and that was it