Which PH meter should I buy?

[vanguard]

I have a two tanks, each with a Neptune Controller. When adding the controller to the second tank its PH read about .3 lower than I expected. I used a cheap YINMIK pH meter I "confirmed" the new neptune was off by .3 compared to my other meters.

After calibrating it repeatedly and buying a new probe it's still "off" by .3. Next, I calibrated the YINMIK pH meter and now it agrees with the "inaccurate" one. A cheap API test kit has my entire family agreeing that none of the colors really match up correctly.

At this point I'm a bit spun around and I don't know what to think. A little research says some of these tools claim to be accurate by +/- .4. What?!?! I can put a piece of tape on the glass that reads 8.2 and be accurate by +/- .4.

Question: I want a PH meter I can trust. What should I buy?

 

[Peair]

I have a two tanks, each with a Neptune Controller. When adding the controller to the second tank its PH read about .3 lower than I expected. I used a cheap YINMIK pH meter I "confirmed" the new neptune was off by .3 compared to my other meters.

After calibrating it repeatedly and buying a new probe it's still "off" by .3. Next, I calibrated the YINMIK pH meter and now it agrees with the "inaccurate" one. A cheap API test kit has my entire family agreeing that none of the colors really match up correctly.

At this point I'm a bit spun around and I don't know what to think. A little research says some of these tools claim to be accurate by +/- .4. What?!?! I can put a piece of tape on the glass that reads 8.2 and be accurate by +/- .4.

Question: I want a PH meter I can trust. What should I buy?

Yea stay away from those cheap meters, I had a Yinmik that I bought from Amazon that lasted about a month, and calibrating it was trouble, it's best to get something good and reliable like the Hanna line of meters.

 

[Nano_Man]

Hanna

 

[shakacuz]

hanna, just not the "egg" checker. i have one and although it has helped, am not convinced its all that accurate. i have a milwaukee mw120 pro that monitors my ph.

most say don't bother testing ph. i would if you're dosing kalk, have a carx, or tank is in a small space

 

[KrisReef]

Yea stay away from those cheap meters, I had a Yinmik that I bought from Amazon that lasted about a month, and calibrating it was trouble, it's best to get something good and reliable like the Hanna line of meters.

The problem with all pH meters is that they require calibration to be accurate and many of them will instruct you to recalibrate them before every use.

Well, maybe not that often, but if you want to know it's working properly you have to test with a known and calibrate.

I bought a Hanna, and I need to buy a new reagent solution to check and see if the meter (almost new!) is broken or if the reagent is expired, but I mention all of this because the Hobby grade equipment has always left me guessing if my pH measurements we precise and accurate, repeatably.

I also am thinking of checking out pH paper to see if that is more repeatable. Hope you find a solution, I have not found one that I am comfortable with, thus far. I hate to calibrate. GL

 

[ReeferLou]

I picked up a Milwaukee pH54 Waterproof pH Tester with Replaceable Probe the other day to replace my backup tester that stopped working. I expect it to arrive in a few days. I use it to see if my Reef-Pi / American Marine PINPOINT pH Probe is off.

I agree it is hard to find a reliable reference that you only need to use a few times per year. Maybe a test kit is better.

 

[Randy Holmes-Farley]

Question: I want a PH meter I can trust. What should I buy?

I describe what I would want below, but not the specific probe recommended is likely no longer sold since this is an old article.

Be sure to get a meter with at least 2 point calibration, and internal temp compensation is plus.

Aquarium Chemistry: Measuring pH with a Meter

This article describes how pH meters work, how to select one to use, and how to best use it to measure the pH of a reef aquarium.

reefs.com

Selection of Combination pH Electrodes

There are hundreds of different types and styles of pH electrodes. These vary in size, composition (glass or plastic sides, typically), shape, the nature of the glass membrane (even non-glass materials can be used), how that membrane is separated from the internal filling solution, (that is, single vs. double junction), whether the internal fluids are sealed or refillable, and a variety of other issues.

For most reef aquarists, the exact nature of the pH electrode doesn’t much matter. Nearly all can give suitable pH readings. Here is my opinion about what is most important to look for:

Selecting an epoxy body electrode instead of a glass body electrode will make it less likely that you will break it by accident. The glass bulb on the tip is still very fragile (I’ve broken many), but the bulb can be protected by a plastic shield to reduce the chance of breakage.If you intend on measuring pH directly in the aquarium or sump (rather than in a cup of water removed from the aquarium), then expect to occasionally get the whole electrode wet (by accident). If it is a refillable type which has a hole for adding more filling solution (usually KCl), then you might get aquarium water into the electrode. That can severely degrade performance by messing up the reference electrode. So selecting a sealed electrode may be a better choice.Some folks argue that a double junction electrode is preferable, and that is likely true. Without going into the design details, a double junction electrode makes it much less likely that there will be any exchange of ions between the aquarium and the filling solution through the glass bulb. This option may be especially important if you are using an internal reference electrode other than Ag/AgCl. For example, if it is a calomel reference electrode, it contains mercury. It is desirable to keep mercury salts out of the aquarium due to its toxicity, so a double junction is likely preferable in that case. Likewise, it is desirable to keep sodium and other seawater ions from entering the reference electrode, and a double junction prevents that to a much greater extent than a single junction. That aspect is more important if you leave the electrode in the aquarium water than if you put in into a storage solution after every use. In general, it is likely better to have a double junction
than a single junction, but it may not result in appreciably better measurements.

There are other attributes of certain electrodes that may make them more useful in laboratories, and hence justify prices that easily range to more than $350 for the electrode alone. There is not likely any significant advantage in using such electrodes for reef aquaria, however. Do not be worried about claims that you need a special electrode for high pH or high sodium environments. That is true for the most accurate measurements at high pH and high salinity, but aquarium water will be OK with a standard electrode, and even brief measurements at high pH (like limewater) will be fine.

An electrode that I have been using for the past few years is sold by Cole Parmer. It is catalog number U-59001-70. It has an epoxy body, is sealed, and has a double junction. I’m not certain what type of reference electrode it contains, but I believe it to be Ag/AgCl. Its list price is $60.

 

[KC2020]

An electrode that I have been using for the past few years is sold by Cole Parmer. It is catalog number U-59001-70. It has an epoxy body, is sealed, and has a double junction. I’m not certain what type of reference electrode it contains, but I believe it to be Ag/AgCl. Its list price is $60.

I need a replacement probe and so I was encouraged by the thought of buying a good one for $60. Unfortuately they've doubled in price according to every source that has them. That's the list price from Cole Parmer.

 

[YOYOYOReefer]

cole Parmer is a great suggestion. You really can’t go wrong with any of their gear it’s all way better hobby aquarium grade . Double junction and refillable probes are nice but like Randy said overkill for our application. a good sealed probe would be my suggestion.

 

[Randy Holmes-Farley]

Yes, I’m not surprised. It’s an older article.

 

[Malcontent]

I just checked and the probe I bought in 10/21 is now 50% more expensive.

 

[vanguard]

I ended up buying this one: https://www.bulkreefsupply.com/milw...ID=710&indexName=brs_prod_m2_default_products

I don't have it in my hands to give a review yet. Even if I did, I'm not sure I could tell you if it has the right reading. However, I hope to calibrate it and gain confidence in it. We'll see. It seemed to check most of the boxes Randy's article said to look for.