Pinpoint PH Monitor reading negative pH?

[RobG]

I've had a Pinpoint PH Monitor for a month now. When I got it, I calibrated it and it's been working well until two days ago. It usually reads somewhere from 8.0-8.4 depending on the time of day.

The thing is reading a pH of -2 (Yup, minus two) in the tank. Now, given that everything is alive & healthy and I can touch the water without my skin burning off, this is obviously wrong.

I pulled the probe out to re-calibrate, and even if I turn both screws on it all the way up, I can't get the number to read even close to the values of the calibration solution.


Any ideas before I send this thing back to American Marine?

[coralsandbar]

Have you calibrated it to both solutions? As I understand it your supposed to go back and forth between either 4.0 and 10.0 or 4.0 and 7.0.

The fineline and right calibration is that both solutions will test out correctly after adjusting the screws. (for both solutions no matter which one you go to). It can sometimes take a little bit fine tuning it.

I am very surprised it would read -2!

Try recalibrating it again using both solutions.

Let me know what happens.

HTH,

Rob

[SCETT316]

Hi Rob:
I had a similar problem, I sent it back to MarineLife. It turned out to be the crystal was cracked inside. they replaced it, and it has been working just fine ever since.
Susan

[coralsandbar]

Thanks Sue,

I was thinking along those lines myself but I didn't suggest it. Makes sense though.

Do you know how you cracked yours, or do you think it just cracked over time?

Thx.

rob

[SCETT316]

I think it was cracked during shipping, cause it really never worked correctly since I got it. It was not visible to me, but that is what MarineLife told me was the problem. I would also like to add that it only took less than a week to get my replacement back, and customer service from MarineLife was great.
HTH
Susan

[coralsandbar]

I guess that makes sense... I managed to pick up my pinpoint in person from Premium.

A lot of people say I am lucky being so close to premium, but I wish I had know about premium 5 years ago when premium was out there all along.

I spent way to much money on a local LFS! (Kicking myself in the head).

I found out about premium through FAMA advertisement and I said, "Damn that's a good price on snails and hermits, I'd better order some. (As I was getting ready to place an online order, the Indianapolis, Indiana clicked. "Hey that's right down the street from work!"

Sorry to go off on a tangent... I help Jason out on Saturday's.


It's good to hear that they got a new one sent out to you in great turn around fashion.

Take care,

Rob

[RobG]

I tried calibrating with both solutions, and no luck (I was using a 7.0 and 10.0). Couldn't even get it close.

I don't know how the crystal would have cracked in mine. It was mounted securly the entire time it was in the tank. It didn't move or get removed once.

Thanks for the info... Guess it will go back. Any of you know the website or contact info for the manufacturer?

[SCETT316]

800-925-4689 ask to speak to Lou.
HTH
Susan

[clyde]

you're not supposed to use 7 AND 10

has to be 4 and 10 OR 4 and 7

[scubadude]

Originally posted by clyde
you're not supposed to use 7 AND 10

has to be 4 and 10 OR 4 and 7

That is incorrect clyde

its 4 and 7 OR 7 and 10, and FWIW I personally think 7 and 10 is the best...as it reflects two closer points that we like to regulate our PH at.

Rob,

I got a new PH Pinpoint monitor the other day and I had some probs w/it as well. I didnt really need one but figured the price that PA was haveing on a sale on them I figured what the heck. Anyway i tried forever to calibrate mine and I could turn the 4/10 dial all day long and the LCD numbers wouldnt change I called Lou at the number Scett posted and he said it may be the crystal too. either way I got it replaced and have one that works now....I think they may have a bad batch floating around right now.

[scubadude]

I forgot to mention....the only other thing that I could think of that may throw it out of whack is the temperature of the calibration fluid...as the foil packs say to make sure its calibrated when the fluid is 77 degrees farenheit...which is pretty close to room temp. in most places

[slash7]

The correct combination of fluids to use for calibration is 4 and 7 OR 7 and 10.

[scubadude]

Originally posted by slash7
The correct combination of fluids to use for calibration is 4 and 7 OR 7 and 10.

You are correct slash....sorry I had a typo :P I corrected it on my post

[clyde]

I looked at my pinpoint on my way out of the house this AM, and I was thinking

DOH!!

then I came to work, yup I was quickly corrected.

you're right

[Biomanjcs72]

Is this. pH is a logarithmic scale, each whole number is a power of ten in the ion concentration. THere is not a pH meter made that will give you an accurate reading over more than about 3 numbers, you have to calibrate for the range where you think you are and go for it.

No body asked the question,. I just felt like chiming in.