Hanna InstrumentsHI98128 pHep 5pH/Temperature Tester, 6-25/64" Length x 1-19/32" Width x 1" Height

I'm a homebrewer and I got one of these for measuring the pH of my grape must. I'm also a cook and a physicist and I like being able to measure the pH of lots of things. This is a nice balance between price and accuracy. This is probably as accurate as you would need for any household application. You need to have a buffer solution to store it in and you should have two solutions for calibrating. It's not trivial to use properly (you should read the manual) but it's not difficult either.

Taking my local extension Master Gardner program we used these to do soil tests. Since then I have started my own lawn care company and I tried cheaper ones with very inconsistent results. The Hanna works very well, plus they have headquarters only a few miles from me!

When your whole aquarium relies on these two fundamental elements you don't really need anything else. Calibration is easy. You get a reading in 15 seconds. Easy to keep an eye on your tank.

I have had this tester for only 2 weeks and it no longer works at all. I followed all the storage and usage instructions, and every day the pH was more than 2 points out of calibration. The last time I turned it on it was stuck at 16 pH and 221 degrees temp and the cleaning solution, ice water, etc wouldn't change the reading. THe battery then died and now with new batteries it won't turn on at all.worst pH meter ever - don't waste your money

I've only used this bout 3 or 4 times so far.My purpose in acquiring this device was to ensure the pH of the wort in my mash tun was staying around 5.4.It takes a few seconds to achieve a final reading which I hadn't expected, but I also had never used a device like this before so I have no basis of comparison. Perhaps all pH meters have a delayed response.The storage solution is placed in the black cap, and since the device typically lays on its back or front when stored, I question how well this works if stored long term. I’m storing mine upright in a Tupperware container that has about an inch of storage solution in it. I don’t bother with the cap.One thing I do like, and which caused me to choose this device over others is the use of standard batteries. No need to try and remember and then find an odd watch/hearing aid battery.To date I’m pleased with this. If I had any experience with this type of device maybe I would have judged this differently. Time will tell.

works well for an entry level ph testing pen. This is less than half the price of the next model up, and tho it may not have all the same features, this pen reads as accurately as pens many times the price. great value

I have used the HI 98121 and now the HI 98128. The 98121 I bought was very slow. It wasn't until I bought and used the 98128 that I realized how fast it should have been. The two big negatives for Hanna is their customer service won't necessarily give you the correct answer to any questions and the fact that it is very hard to keep the pH probe moist at all times with the design of the cap.The cap is not liquid tight, so when you put a few drops of storage solution in it, if you don't keep the meter upright at all times, the storage solution will drain out. Plus, it's a very small resevoir, so you have to constantly top it up. Very poor design for a critical function.If you get a properly functioning meter and keep the probe moist with storage solution, it will perform very well. The meter is advertised as being water *proo*, but I was told by a support person that I should not submerge it to a depth of 18", whihc is where you should sample your water from. I can say that even though he said that, I used the 98121 for about 6-7 years before the seals failed and I always submerged it to at least 18" and sometime as deep at 36".All said, it is so much easier to keep you pH at a consistent level with a meter, rather than a drop test. It's measures down to 2 decimal places which allows you to see what direction your pH is headed before it gets out of hand. The drop tests are graduated in whole numbers of 2 points, ie:70, 72, 74, 76, etc..Using a pH meter has made keeping my pool clear and balanced a much easier job.

This tool has been a great investment in my winemaking adventure. It has been very dependable. It is relatively easy to calibrate. It is much smarter than I am! Yes,........ I would buy this again!