ph calibration need help asap

I've just went to calibrate my ph tester and its all over the place, this is the first digital ph tester i've had though and the instructions were crap and didn't give you much info on what to do with it. with the buffers, do you only use them once to calibrate it then chuck them and use new solution or what? I'm trying to calibrate it and its not givin me the right readings, eg i used the lower ph solution, calibrated then done the higher one and calibrated that, tried it on tap water and its no comin up at 7.0, which is what my tap water is. anybody with any info would be appreciated, sorry if i sound like a numpty/doughball but need to get this sorted asap!! when i first got it i used the calibration solution and put it back in its bottle as it only came with a wee bottle each of the stuff, was that wrong or what?? someone help me please!!

Ok im not 100% clear on what your saying.
Are you confusing Ph Calibration fluid with ph up/down fluid?

If you have calibration fluid,dip the tester(meter) in a cup of it and adjust the screw or dial on the side of the tester until the screen reads whatever ph number your calibration solution is ( usually 4).
Or use your tap water and adjust it to 7 if you know your tap water is 7.
And yes never reuse calibration fluid.
The packet of calibration fluid that came with you tester is only for 1 use,Its not pricy to buy and you can get it in any head shop or online.

hi kully thanks for that yep its the calibration fluid i'm asking about, i was just a bit unclear, think i must have contaminated the fluid as i just put it back in the bottle and now i can't get a proper reading, never mind you live and learn eh! must get some more stuff tomorrow, cheers:thumbsup:

be sure to keep that sensor nice n moist, not wet, but moist. yea look for the packets of cal solution. only a $1.50 here at the pet store so pretty easy to check accuracy, fairly cheap too.

if u no ur tap water is 7 use that 2 calibrate u tester an calibrate 2 7! lol

do you need to calibrate it to the lower 4 ph as well? or just use tap water to cal to 7 and it should be ok? also the tester i've got has got the glass sensor and it didn't say anything about keeping it moist, does that apply to all testers or just some makes?

Quote:

---

Originally Posted by BoomBoom82

if u no ur tap water is 7 use that 2 calibrate u tester an calibrate 2 7! lol

---

Don't listen to this advice.

The buffers (calibration fluid) are reusable for quite a while as lo0ng as they do not get cross-contaminated. Keep them tightly covered between uses.

Tap water does not have the correct ionic strength to give a reliable calibration, and you have no guarantee that it is not going to fluctuate ever.

Don't let your probe dry out entirely. Some probes I think you CAN let them dry out, but if yours came with a little rubber condom thing to protect it, and it has a bit of cotton wool in the tip, keep that moist and keep the probe in there.

If your probe gets cruddy wih organic buildup, you actually can use acetone to VERY gently clean it. Rinse well.

thanks for the advice stinky!