One thing to be aware of with electronic pH meters is that there is a difference between resolution and accuracy. Most pH meters have a resolution of 0.01, but if you look closely the accuracy is +- 0.2! Some of the higher end stick units have an accuracy of +- 0.1 To get accuracies greater than that you need to goto lab type instruments.
Problems Measuring Ph - Which Test Can I Trust?
- Thread starter WaterBeast
- Start date
dschlic1 said:
Hi, Rob from HM Digital again. That's very true, and very observant!
HM Digital's PH-200 has an accuracy of +/- 0.02 pH. We have an excellent warranty and customer service, and we're supremely confident that you'll be very impressed with our products.
The PH-200 also features automatic digital calibration with manual digital fine tuning, which means that calibrating the unit is a simple matter. Each unit also comes with a pH 7.0 buffer (in powder form).
They are!sredish said:more discussion on the pocket testers, what about some of the LaMotte ones? EDIT: looks just like the Oakton unit I just googled... hmmmm says .01+/-
Just to add a little fuel to the fire...
Last week I purchased a Taylor 9058 comparator and I'm really pleased with the results. I have a TF-100 test kit but I've had a very difficult time reading PH. With the 9058 it's MUCH easier. I started by using 10 drops of R-0004 just to get a more distinct color shade but now that I'm used to the reading I use the 5 drops that the instructions recommend.
Last week I purchased a Taylor 9058 comparator and I'm really pleased with the results. I have a TF-100 test kit but I've had a very difficult time reading PH. With the 9058 it's MUCH easier. I started by using 10 drops of R-0004 just to get a more distinct color shade but now that I'm used to the reading I use the 5 drops that the instructions recommend.
Just to make sure eveyone undestands, this is NOT a direct replacement for the comparator in the TF100. It uses a different ph reagent, R-0004, and NOT the R-0014 used in the TF100 so different reagnents would need to be purchased also. Personally, I have both and find I use the one in the TF100 more often. The colors are the same since they both use phenol red reagent, the only difference being the size of the sample used. The larger sample (45ml) used withthe 9058 comparator will give a bit greater precision on the acid and base demand tests (which ARE available for either comparator) but the colors of the phenol red pH test are VERY close on the two comparators since the color intensity is compensated for by the concentration of the respective indicator solutions.austinnichols101 said:
I believe that you have just trained yourself to read the test a bit better and I think you will find that either comparator will be as easy to read now.
waterbear said:
You're absolutely right - the original test is much easier to read now.