For what it is worth, I made a table of results using these tests, each one being performed immediately after the prior one:
RUN #1: Tested sample with "Regular" Precision
RUN #2: Tested sample with "Regular Precision
RUN #3: Tested sample with "High Precision"
RUN #4: Tested sample with "High Precision"
Next Row in Table shows Salfert test results on same sample (and
*ICP result from 5 weeks ago for Na, just out of curiosity)
RUN # 5: Multi-Reference Solution (High Precision)
RUN #6: Multi-Reference Solution (High Precision)
Multi-Reference Solution's Reference numbers.
| PARAMETER | CA | MG | K | Na | NO3 |
| 1st Run (Reg) | 454 | 1370 | 435 | 10,754 | 6 |
| 2nd Run (Reg) | 454 | 1367 | 435 | 10,754 | 3 |
| 3d Run (High Precision) |
441 |
1311 |
429 |
10,605 |
12 |
| 4th Run (High Precision) |
445 |
1317 |
430 |
10,621 |
5 |
| SALIFERT/ICP* | 440 | 1335 | 390 | 10,269* | 1 |
| | | | | |
MULTI-REF
(TEST #1) |
411 |
1317 |
382 |
10,610 |
11 |
MULTI-REF
(TEST #2) |
427 |
1384 |
388 |
10,729 |
4 |
MULTI-REF
(REFERENCE VALUES) |
420 |
1300 |
390 |
10,700 |
11 |
I know that there aren't enough tests performed to make any of this statistically significant, but some may find some of this interesting. My thoughts on these limited tests:
1) The first two runs ("Low Precision) yielded excellent results.
2) The next two "High Precision" RUNS seem acceptable, but the high NO3 of 12 is a little disappointing.
3) I know we aren't supposed to compare these readings to test kits but it has been test kits that I have been relying on for many years to target levels that have given me much success. It doesn't hurt to compare them and keep in mind the differences, going forward, at least for me. (I have compared many brands of test kits with many ICP tests over the years and have found the Salifert kits to correlate fairly well with them).
4) I know that comparing Na to a ICP test from 5 weeks ago is of minimal significance, but I will say that my ICP Na results have historically always been a little low.
4) I'm a little disappointed that the two tests on the Multi-Reference solution are not closer to being the same for Ca, Mg, and NO3; and, that some of the parameters aren't closer to the Reference Values used to make the Multi-Reference Solution. The fact that there are these differences makes me wonder if it can be said that the IOND is more accurate than ICP testing.
5) For me, the IOND is an interesting "toy" to play with but I would never use it to control dosing (nor would I do that with the KH Director). I will probably use the IOND once a week and continue comparing it to my test kits until I am comfortable with a trend, if a steady one develops. Like with any instrument, one must always be leery of it's accuracy. And, as
@CEReefer suggested, I see no reason to NOT always run the tests on the High Precision mode.
6) When I purchased the IOND, I was mostly interested in the NO3 monitoring, and this is the one parameter that I have the least confidence in after these limited trials which is a little disappointing. But, if the IOND NO3 values are accurate, then they are much higher than the Salifert NO3 results that I have been monitoring for years! (But the big question: which values are the accurate ones considering the range I got?!)
All in all, I'm glad that I have this instrument. I will continue to monitor it and repeat some of these "comparison tests" again in the near future. I would guess that it might take a little time for the unit to "break in" and possibly rid itself of some unseen microbubbles that may be in the tubing of a new set-up.
Hope this is of some interest to any of you!