rogierfvv
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3rd time around aquarium keeper, observer, learner
Posts: 84
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Post by rogierfvv on Jul 11, 2016 20:09:45 GMT -5
for the longest time - for decades - I was used to the API PH test. Sometimes I tried the strips, but I found them hard to read.
Professionally I used Hanna pH testers, but never used them on my aquarium, until recently... when I got a Hanna pH tester.
Now, I am finding inconsistencies...
I did calibrate the thing to 7.0, and that seemed to work fine.
And my aquarium water is around pH 6.95 (according to my Hanna pH tester) in my main tank... and suddenly I had the urge to try the old API test with the three drops... whoops!!! 6.4 (or so). That's a big spread... and now I wonder who is worse Hanna or API?
I tend to trust the Hanna device, but... 40 years of history with API is not easily forgotten, so I am puzzling over this... I first wanted to get some feedback... and but if nothing conclusive shows up, I am going to re-calibrate the Hanna tester...
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Post by Carl on Jul 12, 2016 8:43:43 GMT -5
This is interesting.
While I have used some Hanna Instruments in the past, I have not used their new pH tester.
I too have used API pH liquid and strips over the years along with others and found these to be reasonably accurate when compared to these others. Others I have used and found very close to the API include the Mardel pH test strips (although I suspect these are exactly the same product as the API version), the Red Sea, and the SeaChem. However this is not proof of any accuracy, as these all have similarities, and may be equally inaccurate.
Carl
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Post by coco on Jul 12, 2016 10:13:53 GMT -5
I had a Hanna PH meter aprx 10 or so years ago. Maybe longer. For the first year or so it worked great. Then I started to have issues with it. The readings would bounce all over. It would drift constantly while holding it in the water. I ordered new bulbs, calibrated it, it just wasn't working right anymore. I was assuming it was just a faulty meter. But, with the money I paid for it, I didn't think it should become faulty that quickly. I never ordered a new one.
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Post by devonjohnsgard on Jul 12, 2016 10:45:26 GMT -5
I think what your finding is typical. I've seen people get maybe three different sets of test and get all different readings. What I've always advised is to just get one test and stick to it. These hobbyist grade test are not meant to be super scientific and since we just need to know trends, sticking to one and seeing how the one test shifts is about as good as it gets.
There could be a number of reasons for differences in different test.
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rogierfvv
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3rd time around aquarium keeper, observer, learner
Posts: 84
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Post by rogierfvv on Jul 12, 2016 12:07:11 GMT -5
Well, yeah. And I have great confidence in Hanna. For some reason I never used their testers at home for the aquarium, but to test some other water systems for human consumption, I set great stock in Hanna, and professionally everyone accepted those readings. I had even taken three meters home which I personally owned, they had been at my office, and I put them on a shelf and never used them. They were TDS, ORP, and pH, all three from 1999. Still never used them for my aquariums, until I recently became a lot more interested in all the water parameters, and I figured it was worth using those meters. Two of them still worked fine, only the pH meter gave me a problem, so I bought the new one from you recently. And now I have to say even with only 3 tanks, the time savings alone justifies using the Hanna pH tester. Whenever you get me that storage fluid, I'll probably calibrate it again, just to be sure, but I'll stick to the Hanna readings, and forget about API. And as to your last point, I tend to agree, changes in water chemistry might somehow affect these tests also. I have a couple of cheap TDS probes, and one of them is off in the low range (near zero), but all three agree pretty closely in the high range...
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chris
New Member
Posts: 19
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Post by chris on Aug 22, 2016 4:58:44 GMT -5
I've become impressed by the pin point PH monitor.
In 2years I've only had to tweak the calibration a handful of times.
I run an API liquid and Seachem PH alert. All 3 are right on the number.
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rogierfvv
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3rd time around aquarium keeper, observer, learner
Posts: 84
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Post by rogierfvv on Aug 23, 2016 11:26:36 GMT -5
After some more experience, I agree, with proper calibration, I find that indeed my API and Hanna Inst pH Checker agree pretty much, but the pH Checker is just that much more convenient. Experience does suggest however that it is probably a good idea to use the storage fluid when you put it away, as the probe should never dry out, and the storage fluid keeps it in optimal shape, and every once in a while you need to clean the probe with the cleaning fluid. I think when I initially purchased it without the storage fluid, I did myself a disservice, as I just stored it with some water, to keep it moist, but then eventually it went off kilter. After cleaning it and re-calibrating it, I am now storing it only with the storage fluid in the cap, and I suspect that will keep it clean longer. Lastly, the Hanna training video is a lot more convenient than the instruction manual... hannainst.com/products/testers/hi98100-checker-plus-ph-tester.html#videoOne thing however, that the Hanna documentation does not make very clear is how often to calibrate. After some experimenting, and consultations with Hanna, I have found a "best practice," and that is: - If you're testing daily, calibrate your HI98100 tester 1-2 times a week.
- If you're testing weekly (or infrequently anyway), calibrate your tester every time.
Further, you don't need to do a multi-point calibration necessarily. For most aquarium work, you will tend to be operating close to the 7.0 level, so that is the only calibration you need to do.
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rogierfvv
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3rd time around aquarium keeper, observer, learner
Posts: 84
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Post by rogierfvv on May 15, 2017 14:07:21 GMT -5
The Hanna Instruments HI98121 combined pH/Temp/ORP tester arrived and it is wonderful. I had a lot of problems with the HI98100, it always seemed to be off, even after I was calibrating it daily. I wrote to Hanna. Maybe my unit was faulty. I can't make sense of it. Just now it gave me a reading 0.85 pH below the HI98121 and the HI98121 was in agreement (within 0.02) with my Seneye reef monitor, and in line also with the old API pH test. And this is based on cleaning the 98100 this last weekend, and calibrating it before I used it today. The response from Hanna was as follows:
quote This is normally an issue with the pH electrode. Typically the electrode will need to be replaced every year or so. They are warranted for 6 months. unquote I am not convinced by that, for I was suspicious of the results of that probe since the start and it has never been right, so I am not spending another penny on it. Plus, given I now have three parallel pH test methods, I have built in checking.
It took me almost 2 years to end up with the ideal setup in my 29G, and I'm almost there, just adding a CO2 system. After that, I'm replacing it with a 65G tank when I win the lottery ;-) Generally, things are working well.
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Post by devonjohnsgard on May 15, 2017 15:48:02 GMT -5
Glad things are going well. I believe others have had similar experiences with the cheaper meter. I didn't even know they sold the electrode separately and I don't that's something they say on the selling page of the item. I'm glad the new meter is working beter. Guess, you get what you pay for? I'm still over here with my strips and 5 in 1
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rogierfvv
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3rd time around aquarium keeper, observer, learner
Posts: 84
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Post by rogierfvv on May 17, 2017 7:48:18 GMT -5
Well, this is an evolving story. The first electronic pH probe I got from you was the HI98100 (which, by the way was invoiced as a 98103, which is different), but what I ordered, and what I received were the 98100. I personally believe that the first one was faulty, period, but that's water over the dam. I made mistakes, and I am now trying to learn from them. It is very tempting to think that a device with a nice digital display that says 7.00 is "accurate." Plus, frankly, some years ago, I was in a water-related endeavor (water filters and electrolysis machines for human drinking water) where we always used the Hanna tools, and they were highly regarded for accuracy and reliability. So, once I got this digital pH probe, and it gave me a reading that was about 0.5 pH off from my API pH test, I initially simply assumed the HI tester was more accurate, but the discrepancies grew and after three months, I started corresponding with Hanna, and found out that I needed to calibrate this thing quite regularly. Frankly, when I first got the unit, I read the info about calibration, and I thought, Oh good, at least I can calibrate it, if it goes wrong. But the manual tells you how to calibrate, not how often... that came out later. So, I adopted a routine of calibrating with the 7.01 reference fluid every week, before I tested my tanks, and once again I fell asleep at the wheel, assuming that NOW my meter was accurate. Then, recently I seemed to have some anomalies with two tanks that tested low for pH, and I was too lazy to bring out my API test, so I just added some alkaline buffer. I kept getting the low readings however, and that is when I began to suspect the tester again. I had already made up my mind to get the HI98121 from you however, because my old ORP probe was becoming unreliable (after 17 years). But also, I had decided to get a Seneye Reef monitor for my main tank, and since the Seneye monitors pH every 4 minutes, I now had a good reference. So, now what I found was the HI98121 agreeing with my Seneye Reef with just 0.02 pH difference, and an API test confirmed the result. It was the HI98100 that was way out of whack - off by 0.5 to 1.0 pH. The probes are warranted for only 6 months, though they might last a year. The name of the game is, you want to always have a cross check, and that is most likely your API pH test. It is amazingly good, with about 0.2 pH accuracy. The specs of the equipment I have now are as follows: - API pH Test Kit. Range 6.0-7.6, accuracy (implied) 0.2 (at least in the middle of the scale, where it matters)
- Hanna Instruments HI98100. Range 0.00 to 14.00 pH, resolution 0.01 pH, accuracy +/- 0.2 pH.
- Hanna Instruments HI98121, combined pH/ORP/Temp tester. Range -2.00 to 16.00, resolution 0.01 pH, accuracy +/- 0.05 pH
- Seneye Reef: pH-monitoring comes as part of a comprehensive monitoring of ph, NH3/4, Temp, and light. Range 6.00-9.00, resolution 0.01 pH, accuracy tbd...
As you can tell, the HI98100 is probably comparable in accuracy to the API test, and it should not deviate very far or something is wrong. So, with all this experience the API test is my first and most absolute reference. I am now going to do a 6 mo test, and compare results. I will follow Hanna's calibration and cleaning protocol to the letter, and my first reference is going to be the Seneye on my main tank, but when I start seeing a deviation, I will know to verify it first with API, and then to do the calibration and/or cleaning routine for the Hanna testers. At the moment, I operate 3-4 tanks, the fourth one is a 10 gallon hospital tank, or emergency tank... In all, taking into account the experience I have till now, I'd say the economics favor the API pH test, although from a convenience standpoint the electronic testers are handier if you have a number of tanks. However the Seneye Reef system is the real answer for my money, and eventually I am planning to replace my 29G with a 65G tank, once I have these systems figured out perfectly. CO2 is next, and I really want to get on top of the KH system in the process to ensure an optimal level, and the more that falls into line then lighting is the final frontier. My lighting is sub-optimal right now, and complicated because a 29G is a tall sort of tank, and I have some hornwort and some duckweed, so the light is being filtered by the plants. But the light meter on the Seneye is going to allow me to figure that out. Right now that's a learning process. Hanna sent out a new probe for the HI98100, but normally you should figure on replacing the probe every 6 months to a year - so again, it is important to have a benchmark, and you always want the API test on hand, since it is not subject to deterioration the way these electronic probes are, and if your tester disagrees with the API test, count on the API to be correct, and the tester to be wrong.
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Post by devonjohnsgard on May 17, 2017 14:17:06 GMT -5
Very interesting experience. Thank you for sharing. I glad to hear the API tests are keeping up too. I know another member here has had some trouble with the Seneye at low pH 6.0 readings.
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rogierfvv
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3rd time around aquarium keeper, observer, learner
Posts: 84
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Post by rogierfvv on Jun 16, 2017 6:56:28 GMT -5
Devon: Seneye specs are 6.4-9.0 pH so below 6.4 Seneye does not even pretend to read pH. See also my notes below regarding KH of the water - at 6.0 KH will be too low for pH probes to work in the first place: Aside from that: I am about to undertake the next phase of serious pH exercises, and I've set it up on my blog here. I am going to be testing the whole apparatus, for I'm installing CO2 in that tank, which means that I will have two permanent pH probes in the tank, the Seneye and the and the pH probe for the American Marine Pinpoint pH controller. I will be testing the Hanna Instruments pH probes against that, and always use the API pH test as the referee. I am putting a new probe in the HI98100 and recalibrating it entirely, and will also be calibrating my new HI98121, and try to do regular testing for at least a month, until I know what devices are most reliable, and the proper way of using them. My preliminary conclusion is that the electronics are great when they work, but it becomes a matter of trust but verify. Before you take action based on an electronic result, first verify the findings with the API test, for it could be that you water chemistry is out of line, or your your probe is out of calibration. With the Seneye, at least in theory, there is no calibration issue for the "slide" is replaced every month, so you always have a fresh one, and it is 'calibrated' by being soaked in the aquarium water for a day (FW) or two (SW) before you install it. The single most important thing for now is to keep the KH at at least 5 or above - so I am aiming at the 5-10 range as "normal." pH probes are not reliable in low KH water, see here. If I manage do these tests for a month or so, I will know a hell of a lot more about what equipment or test methods I can or cannot trust. The whole experiment seems to be full of the old story that changing your routine is fraught with problems, and it simply takes a while to build a new routine, and know your bearings again. I know this, in the 80's I had a 125 gallon tank in my living room complete with a Dupla CO2 system, and I never had a problem. It always checked perfectly against my API test, and I had that tank at a constant pH of 6.8, but I would still verify against the API pH test at least once a month or so.
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Post by devonjohnsgard on Jun 16, 2017 8:28:40 GMT -5
Happy testing. Your results will be interesting.
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Post by Carl on Jun 16, 2017 9:05:02 GMT -5
If I manage do these tests for a month or so, I will know a hell of a lot more about what equipment or test methods I can or cannot trust. The whole experiment seems to be full of the old story that changing your routine is fraught with problems, and it simply takes a while to build a new routine, and know your bearings again. I know this, in the 80's I had a 125 gallon tank in my living room complete with a Dupla CO2 system, and I never had a problem. It always checked perfectly against my API test, and I had that tank at a constant pH of 6.8, but I would still verify against the API pH test at least once a month or so. This says it all for me, as I have found the API and other test kits worked just fine and in fact NEVER let me down. Are they good for exact scientific testing? No, but for keeping even advanced aquariums both FW & SW, these are more than OK. Carl
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rogierfvv
Full Member
3rd time around aquarium keeper, observer, learner
Posts: 84
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Post by rogierfvv on Jun 21, 2017 6:18:28 GMT -5
Like everything else, there's a learning curve... It would seem to me that in the 80's when I had a 125G with a Dupla automatic CO2 system, I never had a problem. It was set it and forget it. I recalibrated it only once in a great while. With the benefit of hindsight, I must assume that my KH was simply high enough to make those electronic probes perform reliably. I always checked my pH at least once a month, but I never had a discrepancy as long as I can remember. In my present set up the water in my main tank tends to low KH, so I have to adjust it all the time, and the electronic probes are unreliable at low KH. The latest info from Seneye and Fisher (who make their probes) is that KH has to be 6 or higher. In short, I am now starting to track it based on keeping KH at 6 or above. The amazing thing is that I have another tank (10G) where the KH and pH have a tendency to stay high - the difference must be in the substrate, for the water is obviously the same...
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Post by devonjohnsgard on Jun 21, 2017 12:12:33 GMT -5
Like everything else, there's a learning curve... It would seem to me that in the 80's when I had a 125G with a Dupla automatic CO2 system, I never had a problem. It was set it and forget it. I recalibrated it only once in a great while. With the benefit of hindsight, I must assume that my KH was simply high enough to make those electronic probes perform reliably. I always checked my pH at least once a month, but I never had a discrepancy as long as I can remember. In my present set up the water in my main tank tends to low KH, so I have to adjust it all the time, and the electronic probes are unreliable at low KH. The latest info from Seneye and Fisher (who make their probes) is that KH has to be 6 or higher. In short, I am now starting to track it based on keeping KH at 6 or above. The amazing thing is that I have another tank (10G) where the KH and pH have a tendency to stay high - the difference must be in the substrate, for the water is obviously the same... Yes, seems like the substrate....
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Post by childofiam on Jun 29, 2017 17:32:51 GMT -5
I have found that it is imposable to use electronic probs in low KH environments. You will get a different reading every time. Electrodes are dependent on proper amounts of KH to be accurate as well as regular calibration as you have found. Like you, I found that even the Seneye device needs a KH of at least 6 dkh in order to work. These are great devices for saltwater aquariums that have high KH but if any air bubbles or algae gets between the slide and the sensor, it will depreciate the accuracy of the device readings. The light meter requires it to be horizontal in order to read lighting and this horizontal position makes the device prone to anything small floating in the water to settle inside of the sensor around and under the slide of which will throw off the pH readings of the meter.
I no longer worry about my pH as I cut my tap water with RO water and the pH is stable as a result. Consistency and stability is the most important thing. I have the Hanna ORP meter with pH/temp and find it very reliable at a KH of 120 ppm. The main thing I watch is the ORP and RH readings of the water.
Richard
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Post by parker002 on Jul 6, 2017 14:45:24 GMT -5
I no longer worry about my pH as I cut my tap water with RO water and the pH is stable as a result. Consistency and stability is the most important thing. Quoted for truth. IMHO, stable pH is more important than getting it perfect.
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Post by childofiam on Jul 7, 2017 10:22:00 GMT -5
I no longer worry about my pH as I cut my tap water with RO water and the pH is stable as a result. Consistency and stability is the most important thing. Quoted for truth. IMHO, stable pH is more important than getting it perfect. Carl has stated this so many times in post over and over again to many peoples.... I give him the credit for teaching me this very important standard. Richard
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Post by devonjohnsgard on Sept 14, 2017 15:14:07 GMT -5
Rogier,
I wanted to pass this along from Hanna. They recommend a 2 point calibration.
"For improved accuracy it is recommended to calibrate in two buffers. It is important to use buffers that bracket the expected value of the sample to be tested. For example, if the expected value is pH 8, the meter should be calibrated using pH 7.01 and pH 10.01 buffers. If your range is 6.2 use 4.01 and 7.01.
Frequent calibration is the best habit to keep in pH measurement because calibration keeps your readings accurate and reliable. All electrodes are based off of slope and offset (the Nernst equation). However, all electrodes will change as they age.
In reality, the electrode won't behave exactly based on the Nernst equation every time. That's where calibration comes in. Proper calibration will make up for an aging electrode by determining its actual slope and offset when using known buffers, and will update the algorithm in your meter to match.
Using pH calibration solutions can also alert you to any damages in the electrode; slope and offset come into play again here. Offset is the electrode's millivolt (mV) reading in pH 7 buffer, and the slope is the mV change per pH unit. If these numbers are off during calibration, that's a strong indication that the probe is damaged, dirty, or too old and needs to be replaced.
Essentially if you are just calibrating for 7.01 you can’t really expect to be accurate outside of 7.01. That’s why we bracket our expected value with buffers.
Most of our meters come with 4.01 and 7.01 buffers."
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