Temperature control with reef-pi

kdx7214

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Okay, I've got a situation with my tank. Right now I have two Eheim (cough) 150w heaters. The thermostats are atrocious and keep the tank far too warm (79.9 - 80.6). I've adjusted them all over the place to no avail. I'm looking at BRS and their titanium heater. I can get it with or without controller. I'd love to be able to control it with reef-pi, but not sure if that would be too hard on the relays or not. I'd like to rely on the thermometer in the heater unless it gets far out of control.

Would it be safe to run just the element off the reef-pi with a relay, or should I opt for the controller and only use reef-pi as an emergency shutoff?
 
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Sral

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To be fair, having two elements with their own control loop trying to regulate the same thing isn't a terribly stable system. Especially if they sit next to each other.

I don't have experience with reef-Pi and the system you are looking at so I wont give you ill advice on that.

I do however see a few things you could do with those old heaters:
  • Test their proper function
    • You could try to take them out one at a time and test them in a bucket with a thermometer that you trust. The bucket will be much smaller than the volume they are designed for though, so you will have overshoot. I would therefore suggest to:
      • fill the bucket with fresh water for each heater (roughly the same starting temperature)
      • set the heater to the desired temperature
      • check with a thermometer at which temperature they stop heating
        • either by watching their indicator light
        • or by logging the temperature vs time every 0.2 °C or 0.5°C (roughly 0.5°F or 1.0°F)
        • look at which point the curve develops a kink
        • you can also check at which temperature the heater switches on again
        • you can use reef-Pi for that and even gather a few cycles to see at which temperature the heater tries to hover :D
      • that kink will probably be higher than their target temperature though (overshoot)
      • the turn on afterwards might be slightly lower that their target temperature
      • if you can't get them to both to somewhat keep your desired temperature, something is probably broken
  • Ensure they target the same temperature
    • with the above method, set both of them to the temperature you want
    • don't trust the temeprature written on them, that might only work when they were new and calibrated
    • that might still not be enough to keep your tank at the right temperature, because it can still be an unstable system
  • Use reef-Pi for regulation
    • If you plan to use reef-Pi anyway you could still use them, just turn them 1°C above the temp you want for safety and let the Pi handle regulation by switching them simultaneously as a 300W heater.
  • Regulate only one heater - permanently run the other
    • basically turn off the regulation on one of the heaters
    • Check of one heater can't reach temperature by himself by shutting one of them off
    • (watch out for seasons though, he might not be able to in winter, but might grill your tank in summer)
    • turn his temperature 1-2 °C above the temperature you want for safety (use the above method, ignore the scale).
    • set the second heater to your desired temperature (again, use the above method, ignore the scale)
    • That way the first heater will keep a low base temperature and the second heater might be able to regulate the target temperature better by itself
    • You can still use Reef-PI as a safety
 
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robsworld78

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Okay, I've got a situation with my tank. Right now I have two Eheim (cough) 150w heaters. The thermostats are atrocious and keep the tank far too warm (79.9 - 80.6). I've adjusted them all over the place to no avail. I'm looking at BRS and their titanium heater. I can get it with or without controller. I'd love to be able to control it with reef-pi, but not sure if that would be too hard on the relays or not. I'd like to rely on the thermometer in the heater unless it gets far out of control.

Would it be safe to run just the element off the reef-pi with a relay, or should I opt for the controller and only use reef-pi as an emergency shutoff?
Reef-pi does a pretty good job at not over switching as you can set a hysteresis level so temp stays between say 75.0 - 75.3.

I use Omron relays, they have 2 durability ratings, mechanical is up to 10,000,000 switches, electrical is 100,000 switches at full load.
 
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kdx7214

kdx7214

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Reef-pi does a pretty good job at not over switching as you can set a hysteresis level so temp stays between say 75.0 - 75.3.

I use Omron relays, they have 2 durability ratings, mechanical is up to 10,000,000 switches, electrical is 100,000 switches at full load.

Sounds like I should just bite the bullet and get that BRS titanium 300w and just use it with reef-pi. That'll just be simpler (and cheaper!) in the long run.

Thanks :)
 

ReeferLou

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here is what I do : I mainly rely on the reefpi to contol the temp between 77 and 77.8, but I also have the heater with a temp above the reef PI point - say 79 If for some reason reef-pi fails, then the heater can limit the temp. You do want redunancy of some sort imho
 
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kdx7214

kdx7214

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here is what I do : I mainly rely on the reefpi to contol the temp between 77 and 77.8, but I also have the heater with a temp above the reef PI point - say 79 If for some reason reef-pi fails, then the heater can limit the temp. You do want redunancy of some sort imho
That makes sense. I've currently got two heaters, and I think I'm going to connect both to reef-pi and let it deal with them. Both of them seem to have bad thermostats and stay on 100% of the time. Right now they're unplugged to let the tank cool from 79.8F.

Thanks!
 

SoundsDigital

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Following this thread. In the process of setting up a reef pi. Got the temperature probe fitted and finding the temperature on my cheap glass heater is quite constant but nowhere near what it says on the dial and altering it doesn’t seem to be linear either. I can turn it half a turn and move 0.5 degrees then another 1/8th of a turn and move by two degrees.

Thinking of setting the heater to my upper limit and using reef pi to control the temperature, possibly using two smaller heaters and multiple probes.

Can it be configured with three probes to identify if one probe is showing differently to the others or not showing at all to use the other probes and issue an alert?

Also would a SSR prove more reliable in the long term? I know an SSR normally switches lower current but two switching different heaters should be fine and with no physical contacts eliminates the risk of arcing and contacts wearing or welding together.

Opinions please?
 

Sral

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Following this thread. In the process of setting up a reef pi. Got the temperature probe fitted and finding the temperature on my cheap glass heater is quite constant but nowhere near what it says on the dial and altering it doesn’t seem to be linear either. I can turn it half a turn and move 0.5 degrees then another 1/8th of a turn and move by two degrees.
(...)
Can't help you with Reef-Pi much yet, but I can give you some thought about that heater:
The Problem might arise from not enough flow around the heater, since he heats the water and measures its temperature in close proximity. Maybe try the same bucket method, if the heater is linear there, it's probably a flow problem. If it is nonlinear there as well, it's probably the heaters behavior (intended or otherwise).
 

robsworld78

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Following this thread. In the process of setting up a reef pi. Got the temperature probe fitted and finding the temperature on my cheap glass heater is quite constant but nowhere near what it says on the dial and altering it doesn’t seem to be linear either. I can turn it half a turn and move 0.5 degrees then another 1/8th of a turn and move by two degrees.

Thinking of setting the heater to my upper limit and using reef pi to control the temperature, possibly using two smaller heaters and multiple probes.

Can it be configured with three probes to identify if one probe is showing differently to the others or not showing at all to use the other probes and issue an alert?

Also would a SSR prove more reliable in the long term? I know an SSR normally switches lower current but two switching different heaters should be fine and with no physical contacts eliminates the risk of arcing and contacts wearing or welding together.

Opinions please?
You can use multiple probes to control a heater or control multiple heaters with the same probe. An SSR would be ok as long as it can handle the current, I think there are some shaped like a deck of cards that should be good. Make sure you verify it doesn't draw too much current on a Pi GPIO when it switches or you'll hurt the Pi. You might need an NPN mosfet to switch the SSR.
 
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Ranjib

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you can use the heater at a set temperature and let reef-pi just monitor to get an understanding of its own hysteresis. In my case i use eheim jaeger heaters that shows almost 1 degree hysteresis. I set them to 81 and let reef-pi control temp at 78 with hysteresis of 0.25
 

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Okay, I've got a situation with my tank. Right now I have two Eheim (cough) 150w heaters. The thermostats are atrocious and keep the tank far too warm (79.9 - 80.6). I've adjusted them all over the place to no avail. I'm looking at BRS and their titanium heater. I can get it with or without controller. I'd love to be able to control it with reef-pi, but not sure if that would be too hard on the relays or not. I'd like to rely on the thermometer in the heater unless it gets far out of control.

Would it be safe to run just the element off the reef-pi with a relay, or should I opt for the controller and only use reef-pi as an emergency shutoff?
Do not rely on reefpi for you heater if you sensor goes dad or loses connection or like mine which while randomly stop working and then start working all by it self the reef pi defaults to zero degrees and you will have boiled fish. It should default to turning off controller of the heater or have a built in default valve to ignore the sensor if like the sensor report back like 60 degrees or something.
 
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Ranjib

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Do not rely on reefpi for you heater if you sensor goes dad or loses connection or like mine which while randomly stop working and then start working all by it self the reef pi defaults to zero degrees and you will have boiled fish. It should default to turning off controller of the heater or have a built in default valve to ignore the sensor if like the sensor report back like 60 degrees or something.
Most of us uses reef-pi for heater control . Some for years . Sensors goes bad all the time , but as mentioned before due to the built in thermostats in heater it should never lead to such cases . Reef-pi will also alert you when the temperature is out of range , so you will be notified as and when this happens. I think you have mentioned this in another thread and I responded why it’s not ideal to turn off the heater (because that’s more risky when we detect sensor is not ok )
 

Wolfw28

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Most of us uses reef-pi for heater control . Some for years . Sensors goes bad all the time , but as mentioned before due to the built in thermostats in heater it should never lead to such cases . Reef-pi will also alert you when the temperature is out of range , so you will be notified as and when this happens. I think you have mentioned this in another thread and I responded why it’s not ideal to turn off the heater (because that’s more risky when we detect sensor is not ok )
Well I should have don’t rely on Reefpi solely when it comes to healters. When it comes to Reefpi and picking a heater I strongly recommend buy one with a built in thermostat to protect your system in case of a sensor failure. I my case I struggle to keep my system cooled without the use of a chiller. So in my case having a sensor fail and turn on the heater in my case would cause a major catastrophic problem for me. Actual after installing an UV sterilizer I removed my heater. Between the UV, 2 main pumps, 3 powerheads, and lighting my system never gets cold enough to need a heater. Speaking of alerts I’m not a programer and don’t know how to right code but how could we use or incorporate push notifications something like this

Home Security System using Raspberry Pi and PIR Sensor with Push Notification Alerts

Or text notifications something like this http://raspberrypi-guide.github.io/programming/send-sms-messages Or How to Send Text Messages With a Raspberry Pi - Circuit Basics. I don’t know about you but there are a lot of people out there that don’t use email much or at all because of spam, but text or push notifications are a quick and down and dirty to get mine and most people attention. Don’t get me wrong I’m not trying to put down Reefpi I think it’s amazing and thank you for making it for free just some suggestions make it better. Thank you again.
 
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kdx7214

kdx7214

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Well I should have don’t rely on Reefpi solely when it comes to healters. When it comes to Reefpi and picking a heater I strongly recommend buy one with a built in thermostat to protect your system in case of a sensor failure. I my case I struggle to keep my system cooled without the use of a chiller. So in my case having a sensor fail and turn on the heater in my case would cause a major catastrophic problem for me. Actual after installing an UV sterilizer I removed my heater. Between the UV, 2 main pumps, 3 powerheads, and lighting my system never gets cold enough to need a heater. Speaking of alerts I’m not a programer and don’t know how to right code but how could we use or incorporate push notifications something like this

Home Security System using Raspberry Pi and PIR Sensor with Push Notification Alerts

Or text notifications something like this http://raspberrypi-guide.github.io/programming/send-sms-messages Or How to Send Text Messages With a Raspberry Pi - Circuit Basics. I don’t know about you but there are a lot of people out there that don’t use email much or at all because of spam, but text or push notifications are a quick and down and dirty to get mine and most people attention. Don’t get me wrong I’m not trying to put down Reefpi I think it’s amazing and thank you for making it for free just some suggestions make it better. Thank you again.

Every cell company out there has an email to sms gateway so you can get text messages from reefpi. That's how reefpi alerted me when a heater failed so I could replace it before everything died.

For the heaters I always use more than one heater, each tied to a different sensor. That way if one sticks in the on position, the other can adapt until I can get it replaced, Never rely on a single sensor.

Rob at robo-tank has created a document on how to use gmail with sms. This mostly works to this day, although the "less secure application" thing has been removed by google. Instead you just use the app password provided by gmail.

 
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Wolfw28

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Every cell company out there has an email to sms gateway so you can get text messages from reefpi. That's how reefpi alerted me when a heater failed so I could replace it before everything died.

For the heaters I always use more than one heater, each tied to a different sensor. That way if one sticks in the on position, the other can adapt until I can get it replaced, Never rely on a single sensor.

Rob at robo-tank has created a document on how to use gmail with sms. This mostly works to this day, although the "less secure application" thing has been removed by google. Instead you just use the app password provided by gmail.

Thank you for reposting the info for text messages. I spent 2 days reading through this thread after using the search tool and was unable to find any information on text or push notifications. Awesome
 

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