So are your heater elements plugged into your Inkbirds, which are plugged into the Apex? This is how I set mine up, using Apex as the kill switch if the Apex temp probe temp gets too high. Curious how you are using yours.
My setup is similar, but with what I think is the opposite of your controller priority.
The forums are littered with heater horror stories, most of which have a sickeningly obvious error in hindsight. I‘ve thought a lot about this. I wanted to talk about heaters and redundancy anyway, so here’s my take:
Principles:
- 2 heaters, each of which is almost enough to heat the tank in winter by itself, and is enough the rest of the year
- Each heater has 2 controllers, one that actively controls it (primary) and one that is a fail safe to shut off if temp gets too high
- Avoid heaters and controllers with high failure rates
- Want to keep a relatively narrow temperature range, so use more accurate/reliable controller as the primary
- Frequent on/off cycles causes wear on the controller and possibly heater
I chose 78.0F as my target temperature, with range of 77.5-78.0F. This is somewhat arbitrary and could easily be a degree or two lower or higher. Stability is more important than the exact number.
I have 2 300 watt Finnex titanium heaters without integrated controllers, because 300w is slightly less than what I need in the winter, and they have a reputation for reliability. I prefer titanium to glass since they seem more solid and less likely to break. I stayed away from integrated controllers since at the time they had a reputation for poor temperature control by shutting themselves off by directly heating up the sensing element. Since then, titanium heaters with integrated controller but separate thermometer have come out and I’d consider them (as the fail-safe, not the primary).
I decided to use my Apex as my primary controller because I feel like it is more reliable overall, resistant to on/off switch degradation, more accurate for precise temperature sensing, and easier to control and monitor with Fusion. Also I have power alarms set to alert if Apex turns on the InkBird/heater but not enough wattage is being drawn (ie dead heater or InkBird). This is another reason to use the Apex as the primary. The temp probe is upstream of the heaters in my sump, along with all the other Apex probes, in my skimmer compartment. The heaters are both also in my skimmer compartment, but downstream right by the baffles to the return compartment. I could have put them in the return compartment, but I wanted them in the same compartment in case I had a return pump issue, so that it would sense the temp increase in the same compartment and shut off, rather than cook the next compartment.
I use InkBird controllers (1 for each heater) as the backup fail safe controllers, set to shut off at a temp higher than I would ever want. 82.0F in my case. I could set it lower, like 80.0F, but I was a little worried about their accuracy, and also because I put them downstream of the heaters in the baffles between the skimmer and return compartments. Also I used to run the tank at a target of 79.0F.
I also have alarms set for out-of-range temp on my Apex.
Apex for each heater is set as:
Heater1: On at 77.5F, Off at 78.0F
Heater2: On at 77.3F, Off at 77.8F
The idea is that under normal use, only Heater1 would be in use, turning on at 77.5 and off at 78.0. When Heater1 can’t keep up in the winter, Heater2 kicks on at 77.3 (along with Heater1 still on) and gets up to temp pretty quickly, shuts off at 77.8. Heater1 remains on the whole time, avoiding on/off cycles. Heater2 is used infrequently, decreasing wear/tear, and making it much less likely to fail when needed.
Each is wired as heater->InkBird->Apex. So when Apex senses low temp, it turns on the InkBird, which then powers the heater as long as it’s not over 82.0F (fail safe).
With this system, there is at least 1 backup for every system that can fail, and alarms or noticeable trends for any given failure so the equipment can be replaced before the second failure can happen.
