@Ranjib
I have a question on the temperature controller. Fooling around with it, I take it there is no hysteresis setting yet?
For example if you set it at 78, the heater goes on above 78 and goes off below 78?
I recall that a hysteresis band may be a 3.0 feature?
As an example there are 2 different ways your home thermostat works to keep the house temps steady.
One method is your thermostat has a hysteresis or "swing" setting. To prevent your furnace from cycling too fast if you set the temp at 78, with a hysteresis of 1 degree, the furnace will run until it is 78 degrees and shut off, and not come back on until the temp drops 1 degree below 78. Smaller swing settings mean the heat cycles more often, larger swing settings make it cycle less often but with more of a temperature swing.
The second method a home t-stat can prevent short cycling is by using a cycles per hour method. If you set the cycles per hour to lets say 6, and thr temperature to 78, every ten mins the tstat checks to see if its below 78, and will run the furnace until it hits the target and shut down. More cycles per hour means a steadier temp, but too many cycles per hour cause the furnace to short cycle and turn on and off too much.
For anyone interested, reef pi already has a cycles per hour method. It can be set up by how often the temp controller checks the temperature!
If you set reef pi temp controller to 78 degrees, and check temperature every 5 seconds, it will read temp every 5 seconds and turn on the heater when it drops below 78, and turn it off when it reads above 78. The longer the check temp interval is set, the less often the heater runs but it will have a longer run time, and you will get a greater temperature swing . The shorter you set the check temp interval, the heater will run more often, but for shorter run times and keep the temperature steadier. No one wants the heater clicking on and off once a second, so this setting can be fine tuned to your specific tank and heater combo.
