Is a product like this possible for the future?

[mids1999]

Would it be possible to make a module similar to this product, but for aquarium use with the Aquacontroller.

Product name Herpstat from spyder robotics.

What it does is control temperature, but it goes way beyond simple on/off control. It varies the amount of wattage that a heating device is able to use.
This creates an extremely stable temperature. Much tighter control then simple on/off thermostat, because it applies just the right amount of power to the heating device.

 

[aquamanic]

I don't see how that would be any better - doesn't it come down to a function of power (watts) vs. time? I think the Apex can control to a tenth of a degree and can cycle on/off to the second. It might make for an interesting test between the two methods (vary power vs. vary time) but in the end, I'd be surprised if there was a difference to the tank temperature.

 

[CalmSeasQuest]

Interesting question - Maybe I've set mine up incorrectly.

I've set the Apex on at 78.0 and off at 78.6 with the heater set at 79. I realize the controller is 1/10 degree per second but would setting it to a 10th of a degree (78.0 on, 78.1 off) cause a ton of cycling to the outlet?

If it's designed for such, I gladly adjust my setting - I was just concerned about how often it would cycle at night with the lights off. Or perhaps reverse it and set the heater to 78 and the apex to 79 so the cycles are on the heater and the Apex acts as a fail-safe?

 

[swearint]

I have the APEX set up to control to 79.5 +/- .3 F. The heater comes ON at 79.2 and shuts OFF at 79.5. For cooling, I have fans that come ON at 79.8 and shut OFF at 79.5. This is for a ~130 g system and it works really well according to the temperature graphs, only an occassional blip outside of range.

You will need to have the heater thermostat slightly higher than the APEX, otherwise the APEX would not be able to control the temp effectively. If the APEX logic attempts to turn on the heat at 79.2 but the thermostat is set for 79.0 then the heater will stay OFF when it should be ON. I use the heater thermostat as the failsafe. Worst case for heating is if the APEX temperature probe fails low or gets removed from the tank/sump it will turn the heater ON but the heater thermostat will act as backup and keep the heater OFF.

Todd

 

[mids1999]

I don't know exactly how this translates to an aquarium, but with a heat mat the temp variance went from .8 over a week down to .2 over a week when I switched control methods. After seeing the difference there, I just had to ask about the aquarium.

This is something I would either love toeare tested, or be told exactly how to test then report my results.

I would hook the Herpstat up to a heater, but it only has 3 default constant power states 10% 20% and 30% while the aquacontroller could have a constantly variable one determined by the aquacontroller, and only power ramps for heating pads. It also does not have sufficent power handling capacity for a tank.

 

[bohannbj]

I was wondering if any other herpers had this idea. It may be a year late, but I have just put this to the test. It is working awesome. My tank is at a constant temp of 76 degrees with no more than a .1 variance for a fraction of a second. The temp probe is just fine in the water and I checked with Spyder, if it shorts it won't damage the unit. I have the old style probes, so if it corrodes I can get their new one with the silicone wrapping. I believe a proportional thermostat is where reefers need to start moving.

 

[mids1999]

Thank you for testing

You have private message

 

[schwaggs]

I have 3 heaters on my ~500 gallon system. Each are programed to come one at .1 intervals, sequentially. This achieves similar results to varying the wattage output of a single large heater. My system stays within .2 degrees until the halides come on at which point the temp climbs until the chiller kicks in. I use a defer statement to prevent chatter around the set points. My 3rd heater rarely kicks in.

Heater 1
Fallback OFF
If Temp_S < RT+-0.1 Then ON
If Temp_S > RT+-0.1 Then OFF
Min Time 002:00 Then OFF

Heater 2
Fallback OFF
If Temp_S < RT+-0.2 Then ON
If Temp_S > RT+-0.2 Then OFF
Min Time 002:00 Then OFF

Heater 3
Fallback OFF
If Temp_S < RT+-0.3 Then ON
If Temp_S > RT+-0.3 Then OFF
Min Time 002:00 Then OFF

 

[nickman]

Isnt there is significant difference between heating air and water as far as wattage goes? Also, is there a comparable amount of air movement in a terrestrial enclosure to that of the water movement in a reef tank and in turn the same uniformity of temp? If i am not mistaken, water has a much higher thermal mass than air and will cool and heat up much slower than air and in turn have slower fluctuations in temp. For instance, using a 1000 watt heater in a small aquarium is total over kill but it will be switched off before reaching full temp. it will cycle more or less rapidly depending on the ON-OFF settings but maintain a stable temp with less effort than a 250 watt heater that wold operate on a longer ON-OFF cycle. On the other hand, a lightbulb or heat pad/strip in a terrestrial enclosure would be better off operating at a lower/variable wattage on a consistant basis given the fact that air does not "hold" heat very well.

Just my 2 cents/ thoughts on this

-nick

 

[RussM]

Nickman, you are right on the money... which is why I think that the concept behind the Herpstat is great for its intended purpose, but has far less value for aquarium use.