Test results vary between meter and drop test - not sure what to do?

[rpoldervaart]

Thanks Waterbear. I was wondering about tempurature effects too. I have the pump suction to about 80% skimmers and 20% bottom drain, so it's probably getting fairly warm water off the top. When I test the water, I fill a test bottle from as far down as my arm can reach, so it's probably a bit cooler than what the skimmer picks up.

Sounds like it's all within a tolerable range. At least now, I have strips, drop test, and the aqualogic, so I'll occasionally test all three to get a general feel for where things are at.

Thanks,
Robert

[PoolDoc]

Just a couple of general comments;

1. I think -- but haven't proved via test standards sent to customers -- that the current version of the salt test is reasonably accurate.
2. "Reasonably accurate" is subject to interpretation from several angles. The test capability is + / - 200 ppm with a 3 ml sample, which I can achieve in my own testing here against a standard. My guess is that field testing, by a wide variety of users may vary +/- 400 ppm (2 drops either way) as a result of technique. This is "reasonably accurate" from the point of view of the test itself. However, as best I can tell, it's also "reasonably accurate" from the point of view of SWG operation, which is to say that the SWG will work alright if you are are supposed to maintain 3200 ppm, and are doing so with my test, but really (due to both intrinsic test variation and technique problems) have either 2800 ppm or 3600 ppm.
3. I'm going to ship complete replacements for the salt test in the first few kits (including WaterBear's) next week. The original version sucked, for a variety of reasons. The reagents are OK, and can be saved.
4. I may be able to begin sending out standard test samples as well about that time. I'm very interested to get better data on how my test . . . and other people's tests . . . perform for a variety of users against a standard.
5. It's been a long summer in the tunnel here, but I think that's daylight I see off in the distance .

Ben