Herpstat 2 performance

Sterant

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Just posting some interesting data. I have been using Hovabator incubators for 25 years and never used an external thermostat. Recently, after adding a very accurate WiFi temp/humidity sensor to one of the incubators, I saw just how variable the temperature is inside.

So, I tried a Herpstat 2 controller and the results are pretty impressive. Here is a graph of the temperature variations before and after the Herpstat 2.

The dotted line is 86 degrees F. The Herpstat 2 varies from 86.1 after a heat cycle to 85.7 just before a heat cycle. So, a total swing of 0.4 F.

Enjoy -

Dan

upload_2017-10-10_11-12-55.png
 

Markw84

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Dan

I have long been a user of proportional thermostats for incubators. Once you actually use an accurate data sensor to track temps over time, it is amazing how much temps swing with an on/off. I think this illustrates one of the reasons we see such inaccuracy in TSD claims. As we get better equipment, I think we will see much more reliable results.

I assume your graph is over a few months? The herpstat part showing a month's results here? The way it looks we must be seeing daily swings in temp as your room ambient changes, each peak probably around 6PM daily?

What data sensor are you using? I use SensorPush. With humidity that stays over 90% for extended periods I start to see inaccuracy in humidity readings as the sensor seems to take on too much moisture. Have you had that issue?
 

Tom

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Fantastic info Dan. I'm surprised that the Hovabator showed so much variation. I realized there was some temperature fluctuation, but I didn't realize just how much.

Now here is the question: Is all that variation good or bad? We know there is variation in the wild, but is a steady consistent temperature "better" for our artificially incubated eggs? Does it depend on species?

@Markw84 I have had that issue with some of my hardware store cheapy units. Both with the kind that go in the enclosure, and the type with remote probes.
 

Sterant

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Dan

I have long been a user of proportional thermostats for incubators. Once you actually use an accurate data sensor to track temps over time, it is amazing how much temps swing with an on/off. I think this illustrates one of the reasons we see such inaccuracy in TSD claims. As we get better equipment, I think we will see much more reliable results.

I assume your graph is over a few months? The herpstat part showing a month's results here? The way it looks we must be seeing daily swings in temp as your room ambient changes, each peak probably around 6PM daily?

What data sensor are you using? I use SensorPush. With humidity that stays over 90% for extended periods I start to see inaccuracy in humidity readings as the sensor seems to take on too much moisture. Have you had that issue?

Mark - Yes - I had to do some cutting and pasting to get those graphs next to each other. The peaks and valleys on the Herpstat part of the graph are the temp changes from heat on and off - so that's over maybe a few days, but the swing is only 0.4 degrees each time. Do you experience swings smaller than that? I have reduced the highest possible output to 75% thinking that would smooth that curve - perhaps I should reduce it more.

I also use SensorPush and find the same issues at high humidity. I often get readings over 100%
 

Sterant

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Fantastic info Dan. I'm surprised that the Hovabator showed so much variation. I realized there was some temperature fluctuation, but I didn't realize just how much.

Now here is the question: Is all that variation good or bad? We know there is variation in the wild, but is a steady consistent temperature "better" for our artificially incubated eggs? Does it depend on species?

@Markw84 I have had that issue with some of my hardware store cheapy units. Both with the kind that go in the enclosure, and the type with remote probes.
Tom - I think all of that is argument for night-time drops of a degree or two (or more). I can't see why temperatures in a natural nest would fluctuate on a frequency less than 24 hours (a full day cycle) and if they did, the curve would be very smooth - not the artificial saw-tooth pattern I show above. It would also seem logical that this would vary based on species / locale.
 

Markw84

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Mark - Yes - I had to do some cutting and pasting to get those graphs next to each other. The peaks and valleys on the Herpstat part of the graph are the temp changes from heat on and off - so that's over maybe a few days, but the swing is only 0.4 degrees each time. Do you experience swings smaller than that? I have reduced the highest possible output to 75% thinking that would smooth that curve - perhaps I should reduce it more.

I also use SensorPush and find the same issues at high humidity. I often get readings over 100%
Dan - I don't know the timeline of your graph as its not shown, but I am betting those are daily peaks not on/off swings. Aren't we seeing about a month's results in that graph of the herpstat? A proportional thermostat will not have on/off peaks. The temperature in your incubator will change slightly though, with changing room temperatures. For example, my incubator is still running now even though no eggs right now. The temp graph for any hour shows a swing of less than 0.1°. However the graph for the day shows a swing of 0.6° with a high at 7 pm and low at 6 am. That corresponds to the room sensor for the room in which the incubator is located that went from a high of 80° at 6pm and low of 73° at 6am. So the ambient temperature where the incubator is located is going to effect the incubator temperature. Without eggs in the incubator an no TSD going on, I am not careful to control that room temp and I see those results now. If I control the room temperature and minimize the swings there, the temp in the incubator correspondingly evens out.

Tom - I think all of that is argument for night-time drops of a degree or two (or more). I can't see why temperatures in a natural nest would fluctuate on a frequency less than 24 hours (a full day cycle) and if they did, the curve would be very smooth - not the artificial saw-tooth pattern I show above. It would also seem logical that this would vary based on species / locale.
Dan & @Tom - I think there is merit to this argument. I remember having it with Frank Slavens about 30 years ago. He was a big believer in nightly temp drops in incubation. Now with much more know about TSD and the effects of incubation temps I'm thinking there is even more to it than just the TSD. We know from studies of many species now that incubation temps dramatically effect the vitality of hatchlings. If we push the extremes, both high and low, the hatchlings end up very weak with diminished righting response and overall coordination. I'm thinking the constant temp at limits to ensure female, invites that possibility. I believe many of the "hatchling failure" babies we see are a result of inappropriate incubation temps, and not just being started too dry. Both issues are causing problems. More and more, I believe it is temperature hours above a certain threshold that produces females. A constant temperature at that high end is potentially harmful. The same happens at the low end of temps in incubation. Mother nature provides the temperature hours not in a constant exposure, but in daily doses broken by a more "optimal" mid-range. The long incubation period of chelonians also provides for a probable lower temp at the beginning of incubation increasing as the incubation continues into the summer. So some of the earlier embryonic development is done at cooler temps. ????

Definately food for thought!
 

Tom

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Tom - I think all of that is argument for night-time drops of a degree or two (or more). I can't see why temperatures in a natural nest would fluctuate on a frequency less than 24 hours (a full day cycle) and if they did, the curve would be very smooth - not the artificial saw-tooth pattern I show above. It would also seem logical that this would vary based on species / locale.
In one of the first two years of the TTPG conference, they had a researcher do a presentation on his observations of wild turtle incubation. I believe the species was a North American Wood turtle. Incubation temp in the nest over the duration of the total incubation time varied from 50F to 139F, with 20-30 degree drops most nights. This was not surface temps, but temps inside the nest where the eggs were. The study concluded when 100% of the eggs hatched into healthy babies.

More food for thought...
 

Sterant

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Dan - I don't know the timeline of your graph as its not shown, but I am betting those are daily peaks not on/off swings. Aren't we seeing about a month's results in that graph of the herpstat?

Mark,
No - the wave pattern you see oscillates every 15 minutes meaning from peak to peak or valley to valley is 15 minutes. So, it would seem that the heating is not as proportional as it should be. I am wondering if you have ever controlled a hovabator with a Herpstat? Perhaps the stock hovabator heating element cannot handle proportional voltage? or perhaps can only handle a certain reduction in voltage and then shuts off?

What type of heater are you running in your incubators?

All of this being said, my SensorPush is not in the tupperware container with the eggs....it is sitting out in the incubator air....but still - I am thinking that if the proportional heating is working properly that my curve should be very smooth with possible ambient temperature daily swings rather than 4 times an hour??

(if I didn't have problems like this I wouldn't be having any fun so thanks for this conversation ;-)
 

Sterant

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In one of the first two years of the TTPG conference, they had a researcher do a presentation on his observations of wild turtle incubation. I believe the species was a North American Wood turtle. Incubation temp in the nest over the duration of the total incubation time varied from 50F to 139F, with 20-30 degree drops most nights. This was not surface temps, but temps inside the nest where the eggs were. The study concluded when 100% of the eggs hatched into healthy babies.

More food for thought...
Well that all makes perfect sense. Nice thing about these Herpstats (if I get it working as nicely as I think it can) is that you can program in a night drop. I do know people that have good success incubating with a night drop - with radiated and other tortoises.
 

Tom

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Well that all makes perfect sense. Nice thing about these Herpstats (if I get it working as nicely as I think it can) is that you can program in a night drop. I do know people that have good success incubating with a night drop - with radiated and other tortoises.

I built an incubator out of a large stand-up freezer. I took the compressor and wiring out and added a 78watt RHP on the floor and ceiling with a 4" computer fan blowing across the surface of each one to make a circular air current in the incubator. I tried to use a Zilla 1000W type $30 thermostat, and I was getting 10 degree temperature swings. Wayyyy too much. On a suggestion from @Markw84 I bought a Helix Controls DBS1000. It holds the temperature within one degree now unless I open the door and leave it open for a few minutes. I see some people worrying about a temp drop when they open the door to their incubator, but this has never concerned me. I'm wondering if I should put it on timer and let it shut off at night? What I've been doing has been working well, with good hatch rates, so maybe not...
 

Sterant

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I built an incubator out of a large stand-up freezer. I took the compressor and wiring out and added a 78watt RHP on the floor and ceiling with a 4" computer fan blowing across the surface of each one to make a circular air current in the incubator. I tried to use a Zilla 1000W type $30 thermostat, and I was getting 10 degree temperature swings. Wayyyy too much. On a suggestion from @Markw84 I bought a Helix Controls DBS1000. It holds the temperature within one degree now unless I open the door and leave it open for a few minutes. I see some people worrying about a temp drop when they open the door to their incubator, but this has never concerned me. I'm wondering if I should put it on timer and let it shut off at night? What I've been doing has been working well, with good hatch rates, so maybe not...

Yeah - thats the problem - tough to risk experimentation when your current process yields good results.

However, I would love to see how it goes if you incubated a few sulcata eggs with a 15 degree night drop. Don't think I'm willing to experiment with radiata eggs quite yet ;-)
 
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Markw84

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Yeah - thats the problem - tough to risk experimentation when your current process yields good results.

However, I would love to see how it goes if you incubated a few sulcata eggs with a 15 degree night drop. Don't think I'm willing to experiment with radiata eggs quite yet ;-)

I wouldn’t do a 15 degree drop. In nature I would think it would only be 2-4 degree drop at night based on my temp readings and experiments. I’m thinking more in the line of a 3 degree drop at night. That in conjunction with a push to 89 half way through incubation.
 
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