I noticed that in the chart for conversion factors reproduced in these journals and in Cervantes' book, the factor for Hanna meters is listed as .5. When I calibrated the 9813 meter with factory 1500 ppm solution, it read 2.0 EC, which is a conversion of .7.
(This meter can read in EC or PPM)
The Hanna manual states "conversion factor - variable, 0.56-0.78"
I contacted Hanna about this. Here is my question and their reply.
Question:
"Hi, I am a bit confused about the conversion factor of this unit. It is listed as "variable, 0.56-0.78" I am calibrating with #7442 (1500 ppm) solution. When adjusted to 1500 ppm, the EC is 1.98, indicating a conversion factor of .76. How does this unit make use of a variable conversion factor? Is it able to sense various calibration solutions? Or is it perhaps somehow programmable?"
Answer:
"The manual does state is varies depending upon the reading [?] but since the Hanna 1500 [?] is made using the .70 scale you would just use .70 as your factor."
So that doesn't really answer the question from a technical point of view, but it might clear up confusion for those using this meter.
In my opinion, PPM readings are useful for detecting trends in your own grow because of the large range, but are otherwise useless and misleading for communicating with others, and a pain in the ass for those who have meters that only read PPM.
(This meter can read in EC or PPM)
The Hanna manual states "conversion factor - variable, 0.56-0.78"
I contacted Hanna about this. Here is my question and their reply.
Question:
"Hi, I am a bit confused about the conversion factor of this unit. It is listed as "variable, 0.56-0.78" I am calibrating with #7442 (1500 ppm) solution. When adjusted to 1500 ppm, the EC is 1.98, indicating a conversion factor of .76. How does this unit make use of a variable conversion factor? Is it able to sense various calibration solutions? Or is it perhaps somehow programmable?"
Answer:
"The manual does state is varies depending upon the reading [?] but since the Hanna 1500 [?] is made using the .70 scale you would just use .70 as your factor."
So that doesn't really answer the question from a technical point of view, but it might clear up confusion for those using this meter.
In my opinion, PPM readings are useful for detecting trends in your own grow because of the large range, but are otherwise useless and misleading for communicating with others, and a pain in the ass for those who have meters that only read PPM.
