How accurate is the Herpstat 1 Basic (redline) temp sensor? How accurate is ZooMed?

[tb144050]

I am comparing digital readings in my incubator before I put it to use.

I have 2 different ZooMed digital thermometers (identical) with their probes located 1" left and 1" right of my herpstat probe.

Left to right, my reading are:

ZooMed: 79.2F
Herpstat: 80.9F (which it is set for)
ZooMed: 80.0F

I am just wondering what to make of these observations. I expect some variation due to "heat waves" but my 2 ZooMed dig thermometers measure .9F and 1.7F LOWER than the Herpstat. The 2 ZooMed's are only .8F different between their readings, so I find that believable or maybe that is just the "acceptable tolerance".

But they both measure .9F or 1.7F LOWER than the Herpstat... What do I trust?? I want to KNOW that I have temp measurement I can trust.

 

[tb144050]

Just checked temps again about 12hours later...haven't touched anything or opened the door (I love that glass door!! )

Still pretty much exactly the same....herpstat and 1 Zoomed were down by .1F (normal fluctuation).

ZooMed: 79.2F
Herpstat: 80.8F (which it is set for)
ZooMed: 79.9F


So the zoomeds I assume are within tolerance of each other? So is the herpstat off by over a FULL 1-degree F? (assuming the actual temp is roughly the average of the zoomeds: 79.5F)

 

[indyana]

Trust the HerpStat. Quoting from the product page:
·Precision sensor with internal resolution of .1125 °F and is accurate to ± .9 °F

ZooMed does not provide accuracy information for their digital thermometers, and given the price tag, I can't imagine they are precision equipment.

 

[tb144050]

Trust the HerpStat. Quoting from the product page:
·Precision sensor with internal resolution of .1125 °F and is accurate to ± .9 °F

ZooMed does not provide accuracy information for their digital thermometers, and given the price tag, I can't imagine they are precision equipment.

Yep, I agree that the Herpstat had better have higher accuracy...lol

But I am still trying to make a decision about which device I should base my temps on. Here are my observations (and I will post my questions below):
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Conditions:
-Herpstat set to 81.4F and the incubator door has not been opened in 24hours.
-Herpstat probe located at center of "female section", dangling in air.
-3 ZooMed temp probes, triangulated and same height, dangling around Herpstat probe, located 12" from each other.

Unrelated Conditions:
-2 ZooMed temp probes located in the Male section, dangling in air, 12" from each other.
-Male section is below female section, and separated by divider.
-Heattape is located below Male section, and separated by divider.

Observations:

1) The 3 female ZooMeds are consistent: usually within .2F of each other, unless the heater is on.

2) The 3 female ZooMeds consistently average 80.6F

3) The Herpstat averages its "set temp" of 81.4F.

4) As temps swing, the ZooMeds (located about 5" away in each direction) are consistently an average of .8F LESS THAN the Herpstat "current temp" display.

Observations Unrelated to the Tested female Area:

1) The 2 ZooMeds in the lower Male area are consistantly an average of 86.2F.

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So here's where I am scratching my head....

Comparing the ZooMeds to the Herpstat, I don't know if my male section is equal to (ZooMed + .8F)?? ....because:
1) That is the consistant average difference and,
2) All 5 of the Zoomeds are consistently average...(confirmed by placing all probes in one place the other day)

............OR..................

Is my male section equal to the actual ZooMed temps?

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Obviously I want my females to definitely be females, and I definitely want males to be males. But I don't want to risk my female section getting bumped into the "mixed sex" temp range.

I just don't know which to trust when 5 consistently-same (within .2F) ZooMeds are .8F LESS THAN the Herpstat's "current temp"....and the ZooMeds are closer to the "heat vents"...so they should, if wrong/affected in any way, be higher...??

 

[indyana]

I'd just assume that the ZooMeds could be plus/minus a degree or two and try to center the areas in the temperature range for their sex as much as possible. There's a little tolerance in there to work with.

If you really want to play the game of trying to determine what the differential is, I'd place the probes extremely close to the HerpStat, and give them 30+ min. to equalize. Then, I'd note the differential on each individual ZooMed unit rather than trying to come up with an average differential. In your first tests, for example, one of the ZooMeds was reading about 1.6 F low, while the other was only 0.9 F low.

 

[tb144050]

I'd place the probes extremely close to the HerpStat, and give them 30+ min. to equalize. Then, I'd note the differential on each individual ZooMed unit rather than trying to come up with an average differential.

The average of them all is usually very consistent. Even each individual reading is usually within .2F of the other ZooMeds in that section. Except....

In your first tests, for example, one of the ZooMeds was reading about 1.6 F low, while the other was only 0.9 F low.

After many more days of testing/observing, I have determined that every so often, I get a Random value...probably because of a "heat wave" or some other thermal pattern or whatever.....but that same probe will usually read within .2F of the other probes. So I am not too worried about an occasional "outlier".


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My main concern is that, at any given time, all the ZooMeds in the female section are consistently about .8-1.0F below the Herpstat's current temp. And all the ZooMeds are consistently "in agreement" with each other except for the rare occasional "oddball".

I just put 6 more ZooMed probes within 3" of the Herpstat. I will observe them for "individual variances" before I put about 3 more into their permanent observation points.

 

[indyana]

Okie dokie, if your tests reveal that all the ZooMed units are consistently below the HerpStat (and that none of the units have an extreme variance), I think it would be safe to assume that the true temperature is up to a degree higher than what the ZooMeds read when you have them in their final locations.

I searched around a bit online to see if I could dig up accuracy information for the ZooMeds, but no luck. Units of a similar design and price range from other companies claim +/- 1 F accuracy, which seems in line with what you're seeing for the ZooMeds.

 

[tb144050]

Okie dokie, if your tests reveal that all the ZooMed units are consistently below the HerpStat (and that none of the units have an extreme variance), I think it would be safe to assume that the true temperature is up to a degree higher than what the ZooMeds read when you have them in their final locations.

I searched around a bit online to see if I could dig up accuracy information for the ZooMeds, but no luck. Units of a similar design and price range from other companies claim +/- 1 F accuracy, which seems in line with what you're seeing for the ZooMeds.

Yep...that's the sum of my whole "issue": I think the Herpstat probably registers up to 1F higher than actual, and the ZooMed's might be consistently .5-1.0F below?? So I can't decide which one to trust.

1) If I trust the zooMed's, I am perfect. But the Herpstat is usually atleast a full 1-1.5F hotter...so I don't want to risk my male section going over 90F (if my ZooMeds are wrong and the Herpstat is right).

2) If I trust the Herpstat, I am at 81.5F (good) but I should assume my male-ZooMeds are wrong...instead of ZooMed = 88.5F average, I would assume "Male section = about 86.5 (which is too low for 'confirmed male').


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^^Note: You might need to save this pic and open in MS Paint...or "Right-click, Set as Wallpaper"...to help you read my numbers.

 

[indyana]

Unfortunately, short answer is that you can trust neither to be reporting the absolute true temp. HerpStat reading should be read as "+/- 0.9 F" and ZooMeds as "+/- 1 F" (at least). It's what you have to work with without investing in high-end monitoring equipment. You can average the groups and try to get the readings centered in the right temp range. If you want to get really technical, even perfect temp doesn't completely guarantee sex.