Which pH meter to get?

[Rook]

Hello Randy et al.

I have a Pinpoint pH meter that is a few years old and which I dropped into my sump Now of course it is not working right and everything has a pH of 2.xx. I'm not sure if it is just the probe or the entire meter that needs to be replaced, but I'm looking at various options for a new meter.

Are there any recommendations or opinions on which meters are better and more accurate?

For example, how does the Milwaukee MIL-SM101 meter compare to the Pinpoint? Stats show as follows:

Specifications:
Range 0.00 - 14.00 pH
Resolution 0.01 pH
Accuracy ± 0.01 pH
Calibration Manual 2 points
Temp. Compensation Manual
Battery type/life 1 x 9V / 300 hours
Environment 0 Ð 50C/95% RH Max
Dimensions 80 x 145 x 35 mm

Portable pH meter fro quick and reliable measurements

# Cloth junction electrode with 1 meter cable
# Manual calibration
# Large and easy to read display


Or, how about the Milwaukee handheld pH testers such as the MIL-PH51, with the following stats:

Range 0.0 - 14.0 pH
Resolution 0.1 pH
Accuracy ± 0.1 pH
Calibration Manual 2 points
Electrode Replacable MA73600
Battery Life 1500 hours of continuous use
Battery Type 3 x 1.5V
Environment 0 Ð 50¡C / 100% RH

Accurate and reliable Waterproof pH/¡C tester

# Double junction replaceable pH glass electrode
# IP67 Waterproof casing



Reeffanatic also makes a pH monitor similar the the Pinpoint monitor in looks.

Are these all just as good or accurate for hobby use? If so, obviously the less expensive brands will get my vote


Thanks

[rick s]

I have the Reef Fanatic. A few of the reasons I chose it were:

1. Bright LED display.
2. The display is always on. I can glance at it from across the room and read it.
3. AC powered
4. No interference issues with it being AC powered.
5. If I remember correctly, the advertised accuracy was decent.
6. Full time Temperature display.

I am very happy with the meter. However, there are 2 things that I wish were different:
1. The pH reading starts to drift upwards a lot sooner than I'd like it to. A quick, simple calibration takes care of it. But I wish it didn't drift.
2. The temperature display always reads 2 1/2 degrees high. I have compared it to many other thermometers. I have tried different temp probes and an entirely different meter. It also read 2 1/2 degrees high. I can trust that it is off by that amount, so I know (from across the room )what my temp is, I just wish it were more accurate.

[Randy Holmes-Farley]

I'd want to see resolution to 0.01 pH unit, and I'd personally like to leave it running in the sump 24/7, unlike a handheld unit.

So I'd vote for the firs tone, but might like one with AC and a probe that was not part of the meter itself.

I describe pH meters here:


Measuring pH with a Meter
http://www.advancedaquarist.com/issues/feb2004/chem.htm

A Comparison of pH Calibration Buffers
http://reefkeeping.com/issues/2005-02/rhf/index.htm

[Rook]

Thanks Randy.

One reason I was not terribly impressed with the stats of the handhelds is that they do not go to 1/100th degree. I never minded the battery on the Pinpoint, it just forced me to recalabrate the meter once in a while

It looks like the first meter has a probe that is seperate from the unit, and thus hopefully replacable! I was just looking to spend maybe $60 versus $90

Do you suspect my meter is dead after the bath?

[Randy Holmes-Farley]

Yes, I suspect dropping it in salt water killed it, but if you can open it up, rinse with RO/DI, and dry it out, it might work again.

[old salty]

Just an FYI,


Any time you drop electronic equipment into saltwater, the best thing to do is to rinse it off immediately (remove the power of course.) If you can disassemble the item, definitely do so. Once it is rinsed off thoroughly, give it a final rinse with RO/DI water. If you have a can of air (sold at computer stores), blow off as much of the water as you can and allow the item to air dry.

Once it's wet, it's wet; the deed is done. More water won't hurt anything, especially fresh water. I don't think I need to go into how corrosive salt water can be. In fact, most of your electronic circuit boards are washed prior to final assembly.

[Rook]

Okay, any opinion on the Vital Sine pH meter? I searched and I see they sell it at several very reputable places inside and outside the hobby.

http://www.drsfostersmith.com/Produc...&N=2004+113762

Would this be better than the Milwaukee or Pinpoint meters, or just more expensive.

[Rook]

Or, this pH handheld by Hanna that goes to 1/100th and the probe can be replaced. This unit is only $26.98

http://www.proaquatica.com/proddetai...c6636a871947d9

"Inexpensive yet accurate, this small pH pen supplies fast and accurate readings. Microprocessor-based, it is great for both fresh and saltwater aquariums and garden ponds. A standard combination pH electrode is included. Measures pH from 0.00 to 14.00. Batteries are included. Six-month warranty. Large and easy-to-read LCD High accuracy with 0.01 pH resolution Two point fast and accurate calibration Usable with virtually any pH electrode Battery life: 3000 hours of continuous use Wide range: 0.00 to 14.00 pH Replaceable pH electrode Product# 98103 - Mini pH Checker"

[Randy Holmes-Farley]

pH pen types need you to hold them. I'd like to separate the meter from the probe so the probe can stay in the tank water, and the meter can be away from it. I also do not know if that one takes two calibration points, but it may.

[Rook]

Yes it does. I'm only looking at 2 point callabration, 1/100th measurement.

I guess my real question is, is this a "you get what you pay for" item. I.E. is a $100 meter necessarily better than a $20 pen meter, assume the all the comparibles have 2 pt cal., 1/100 measurement. I'm looking more for accurate pH readings than anything else. Although I see the Vital Stine also measures temp and can measure ORP, and apparently is waterproof (for dummies like me who drop them).

I just don't want to spend $100 on a meter if I can get the same accuracy with a $20 meter.

[Randy Holmes-Farley]

Yes, I expect a $100 meter is substantially better than a $20 meter from the same company. But for most reef applications, I'd get a $20 meter before a pH kit, and it may be suitable for most reef applications.

[Rook]

Hi Randy, a followup question.

What type of probe is best / most accurate? I've seen single junction and double junction probes;cloth junction; Ag/AgCl; epoxy sealed;

What is best? Keep in mind I have no idea what any of that means

[Randy Holmes-Farley]

Double junction sealed is best for our purposes, IMO. Single junction is OK. Gel filled is good.

Here's a nice pH electrode (but you need a meter to go with it):

http://www.coleparmer.com/catalog/pr...5900170&pfx=EW

All you are likely to buy are Ag/AgCl.

[aquarius77]

The new electrode on the pen tester costs 18 bucks! You would think the whole unit for 26 that the probe would be somewhat cheaper.
I would be satisfied with a pen tester i think esp for that 26 dollars. I watch expense as much as i can, im on a tight budget. Thanks for the link!

[Randy Holmes-Farley]

You're welcome.

Good luck.

[Rook]

Originally posted by Randy Holmes-Farley
Double junction sealed is best for our purposes, IMO. Single junction is OK. Gel filled is good.

Here's a nice pH electrode (but you need a meter to go with it):

http://www.coleparmer.com/catalog/pr...5900170&pfx=EW

All you are likely to buy are Ag/AgCl.

Thanks Randy -yes

I've been reconsidering my options and looking into a Aquacontroller unit. They use single junction probes, but perhaps I'll be better served to spend a couple extra $$ to get these Cole Parmer pH and ORP probes

[Randy Holmes-Farley]

The might sever better if you intend to leave them in the tank water 24/7.

[yraveh]

Randy,
Where can I read about ph probe. I want to understand the specification. Namely what does " Double or Single junction, sealed, Gel filled and Ag/AgCl " mean.
Thanks

[Randy Holmes-Farley]

Much of that info is here:

Measuring pH with a Meter
http://www.advancedaquarist.com/issues/feb2004/chem.htm

and this may be useful:


A Comparison of pH Calibration Buffers
http://reefkeeping.com/issues/2005-02/rhf/index.htm

[yraveh]

thank you!

[Randy Holmes-Farley]

You're welcome.

Good luck.

[Rook]

Thanks again. After all this I ended up going with an Aquacontroller Jr. and their probe (I got a good deal) but I'll be using the probe you pointed out when I need a new one.

[Randy Holmes-Farley]

Sounds good.

Happy reefing.

[yraveh]

Here's a nice pH electrode (but you need a meter to go with it):

http://www.coleparmer.com/catalog/pr...5900170&pfx=EW

All you are likely to buy are Ag/AgCl. [/B][/QUOTE]


Randy,
Good Morning. I contacted Cole-Parmer regarding your recommendation. Iwas confused with the fact that the specification mentions that it is not for high Na+ .
The tech support rep. discouraged me from buying the electrode. He claimed that it would last only a year. He recommended the following:
http://www.coleparmer.com/catalog/Pr...u=0599512&pfx=

What is your opinion? is there any other brand that uou recommend?
Thanks
Yehuda

[Randy Holmes-Farley]

Almost no one in reefing uses special and expensive high sodium electrodes. I'm not sure if that is one, but any double junction electrode will be fine in our application.