Help PH PROBLEM!

[Off The Deep End]

Ok so i bought a used ph monitor(milwaukee) 2 months old (2 month old probe) it was shipped wet. When i first installed it my PH read 7.7 so i adjusted the ph to 8.0 in the morning up to 8.2 at night. I then decided tonight to just double check the monitor and calabrate it, now here is where i got stuck. when i put the probe back in it read 7.5 (after calabration) could it really have been that low and every thing look healthy in the tank? I already raised it up .5 and now i need to raise it another .5+ So that would mean my original pH was 7.0-7.1. the other issue is with my test kits it is reading 8.2 and my monitor is reading 7.5 what to do??

 

[murfman]

Sounds like your probe has issues. You could soak the probe in 4.0 solution for 4 days and then calibrate it again. That or get a new probe. Take some of your water to the LFS and have them test it for you.

 

[Off The Deep End]

Good idea murf! Do you always calibrate the slope too? or do you just calibrate the front?

 

[stugray]

"Do you always calibrate the slope too? or do you just calibrate the front? "

I think you just found your problem.

You MUST have at least two points to calibrate a pH probe.
That way you calibrate the slope.

I use the 4.0 & 10.0 to calibrate my probes going back & forth multiple times until it's dead on at each point ( rinsing in RO/DI each time ).

Then I check it with some 7.0 just to be sure.

Stu

 

[Off The Deep End]

Thanks Stu! I had a feeling that i screwed it up lol. So is the reason you use 4.0 & 10.0 just so you can triple check it with the 7.0 or do you have other reasons behind it?

 

[jreeceaspen]

I use 10 and 7, which right in the American Pinpoint Instructions it says to do. Either that or 4 and 7. You need to go back and forth till it balances out.

 

[Off The Deep End]

Thanks everyone, it looks like i made something really easy into something difficult.

 

[murfman]

I calibrate my AC Jr probe with 4 and 7 ( it will be working in solution be low 7.0) For my Milwaukee, I calibrate between 7 and 10, since it is in the tank and will be working in the 8.+ range. I too rinse between calibration solutions.

 

[Off The Deep End]

Ok so i went out and bought some 7.0 & 10.0. Should you have to turn the front dial and back dial for both of them? the closest i can get is 7.0 in the 7.0 solution, then when i put it in the 10.0 it goes to 9.2, the rear adjustment cant go up any higher so i would have to adjust the front one but when i do that it changes the 7.0 reading and its not getting closer. Am i doing something wrong? any help is appreciated.

 

[Off The Deep End]

On another note is it normal for it to say that my tapwater has a higher ph than my saltwater?

 

[murfman]

It really sounds to me like your probe or meter is bad. Your tap water should be between 6.5 and 8.5.

http://www.freedrinkingwater.com/water-education/quality-water-ph.htm

 

[Off The Deep End]

Yeah it just seemes that everything is backwards my tapwater is reading 9.6 when my saltwater reads 8.0. So does anyone local have a good probe that i can try to find out if its the probe or the meter?

 

[stugray]

If you brought the whole thing over to my place, we could check it against mine & I have calibration solution.

In Longmont

Stu

 

[Off The Deep End]

Yes Stu that would be great! When would you be available?

 

[murfman]

Let us know what the issue was.

 

[Off The Deep End]

Will do Murf!

 

[Off The Deep End]

Ok first i want to thank all of you for your advise & help. Second i would like to thank Stu for taking the time to help me test the meter & probe. That being said we have a solution, its the probe. After trying to calibrate the meter and failure we hooked up one of his probes, we calibrated it and bingo it worked great! Once again thank you all for your help and Stu thanks for the help and frags!

 

[stugray]

No problem! Hope everything works once you get a new probe.

Your welcome for the frags. No-one leaves my place empty handed.

Let me know if you want to do the LED night lights. A buckpuck is ~$25 w/ shipping and two LEDs are ~$15. Total $40 for essentially the same night lights that I have.
My labor is cheap - I work for beer ;-)

Stu

 

[murfman]

Dillon, try soaking the probe in 4.0 to recharge it. Can't hurt, right?

 

[Off The Deep End]

The guy i bought it from is going to give me a refund and then i think im going to go with a RKL or ACjr, any advise on which one you all perfer?