Dual heaters in 55 gallon tank with heat controller

Recently, I installed two Aqueon Pro 150 watt heaters in the 55 gallon tank with a ITC 306t controller by Inkbird. I've read how so many people using this controller use the controller to determine and maintain water temperature constantly turning on and off ones heaters. I am using my controller as an insurance plan. I decided to set my Temp. Set (TS) on the controller to 81 degrees. I set my two heaters at 78 degrees. With this, my controller is constantly 'on' providing power to the heaters until 81 is reached which it should not. The two heaters do their thing with their own internal thermostats to heat the tank to 78. The heaters can go on and off because the controller is allowing power to the heaters as though it is trying to get to 81. But the controller TS is never reached because the the two heaters shut off at 78. Now....should one or both heaters go crazy and remain on overheating my tank, the controller kicks in and when 81 is reached, cuts power to the heaters.

I much prefer to have it set this way for protection. Cranking the heaters up so the controller does all the tank temp monitoring is dangerous. If the controller goes bad.....the fish might boil because the controller would allow the heaters to remain on past the 78 setting. If the heaters go bad because instead the set up is for heater thermostats to do the work, the controller will automatically cut power to the heaters if the temp reaches 81 degrees thus preventing overheating. I'd prefer to let the tank cool down without heaters on when the controller stops the overheating than coming into the room and finding a 95+ degree tank with dead fish. Replacing a heater with a new standby ( which we should all have on hand) is no big deal. Plus, if one of the two heaters goes dead, there is another one to at least keep a portion of the water warm.

These are just my thoughts and others may not agree, but my goal here is to heat the tank with no possility of overheating it. Btw.....allow plenty of time for the heaters to raise the water to heater desired temp. Mine took hours to get all that tank water set at 78. My controller sensor is located just off center with the two heaters at opposite ends of the rear tank wall set vertically as recommended by Aqueon. Moving water is near each heater for uniformity sake. My controller is set for no timing because I want a constant temp day and night. This is a heat on and off unit only....no cooling.

The Inkbird Controller directions are not ideal, but with a bit of research, one can work it ok. If many out there need a step by step, I will gladly post a detailed step by step.

My tank is a similar size to yours but i use 2 300w heaters.

I have nowhere near as much worry, my 'backup' is a basic 300w with a thermal switch that is set (ignoring the useless numbers on the thermostat) with a thermometer to switch at 23 deg. That kicks in if i get a bit carried away with a wc.

My electronic heater, also 300w that has an electronic thermostat is very accurate (again, checked) and displays the actual tank temp.
That is my main and is set at 26, the ideal for my fish. The electronics mean that the tank never goes above 26.

Works well and causes zero worry.

Cynic,

Glad all is well. My concerns center around one of your heaters going crazy. What will stop it from overheating your tank? I may have missed something in your response, but I am not willing to trust my heaters alone even if they are of quality. The controller will not allow overheating that could arise from even the best of heaters malfunctioning. My heater thermostats seem to be working just fine. But I know many out there do not.

Is the thermal switch you mentioned able to shut the heater off? In other words, is your heater set to be on all the time with the thermal switch doing the monitoring of on and off? If so, what would stop the heater from staying on if your thermal switch got stuck 'on'? Your set up works for you and I'm glad, but I'm a nut for insurance against the overheating. In my set up, the heaters do their thing and should the water temp get too high, all power to heaters goes off via the controller.

Respectfully, RBT

RetBioTchr- I think I know the answer....but does this turn back on if the water gets back to the right temperature below 81? Or do you have to do something manually? Also, do you have a link to this? I'm just curious about it. Lol. It does sound like great insurance to me!

Yes it does. If the water temp goes to 81, the controller shuts off power to the two heaters. And when the temp falls back below 81, the controller provides power to the heaters to do their thing. Remember, though, that the heaters have their own thermostats to heat to 78. Should they ever go too high, this unit prevents a temp higher than 81 by shutting off heater power.
The controller, as I've set it up, does not monitor the fluctuating few degrees around the 78 that the heaters do. It only prevents temps from rising above 81.

I know it's a bit confusing, but it's sure worth it to me.

http://www.ink-bird.com/products-temperature-controller-itc306t.html

https://www.amazon.com/dp/B01486LZ50/?tag=ff0d01-20

So you have a thermostat controlling things in case a thermostat fails...

The bit i don't get is my 300w heater cannot heat my tank over 28deg, period. I tried years back when i had an itch breakout and couldn't heat the tank high enough. That's why i bought another heater.

I would need both heaters to fail 'on' to get the issue your worried about, kit for kit sake for me i think.

I'm using a very similar configuration to this in all of my tanks. Heater controller switching two separate 'small' heaters. On mine, the heater controller deals with the temperature regulation; the tank is set for 24.5c on the controller and the two heaters are both set for ~25.5c. With it set like this, the thermostats in the submersible heaters never switch, unless the heater controller gets stuck on! In the rare event the heater controller gets stuck on and one of the heaters gets stuck on, the heater is specced as such it has very little chance of taking the tank much above 26c. On the main display tank, fans will also kick on preventing anything from overheating!

Have been a little paranoid about this after a good friend of mine lost all of his fish when a heater took his tank over 40c! The Inkbird units look like a nice compact solution, I'm personally using industrial temperature controllers that are stupidly overkill for what I need them to do. As the Inkbird units are selling for £12.99 on Amazon I'm going to pick one up for the quarantine tub I keep running in the spare room hehe.

In my 60g I'm just using an external Finnex controller with a 500w titanium heater. It has the highest independent rating for reliability. It's been running for about a year and maintains a +/- 1 degree variation. I have no concerns.

Edit: In a 'past life' in industry (monofilament extrusion) I learned that reliable temperature controllers are the key to success in ensuring long term thermal control. I think the external controller is more reliable than internal heater thermostats.

I'm glad you are successful and pleased. I agree abt the controller being more accurate? My idea was merely to use the heater unit thermostats with the controller as a backup shut off device. I'm in no way telling all what to do or that my situation is perfect. What works for you is obviously pleasing you. I was trying to share my thoughts so as to avert a potential disaster for those who might tend to think along the lines I do.

Hmm....I understand both sides of this debate. Lol. I think....if I was to get a controller....I would decide to use it by, before anything (fish or plants) is in the tank....turn up one or both heaters all the way and see what the temperature gets to. If it gets too high for me to be comfortable, I think I would go with the way RetBioTchr. If it didn't get real high, maybe the other way is better.

AbbeysDad said:

Edit: In a 'past life' in industry (monofilament extrusion) I learned that reliable temperature controllers are the key to success in ensuring long term thermal control. I think the external controller is more reliable than internal heater thermostats.

Click to expand...

Does this mean the heater will last longer if controlled by an external controller instead of its internal one?

cowgirluntamed said:

Does this mean the heater will last longer if controlled by an external controller instead of its internal one?

Click to expand...

There's a couple of separate things in play here. I believe that the external controller is more sophisticated/reliable than the internal thermostats in many/most aquarium heaters. The heater itself is a nearly indestructible titanium rod heater. These typically have a very long use life.

I should point out that prior to my current heater setup, I had two Aqueon 200w heaters in the tank independently sharing the load. This worked well for quite some time after I got the settings dialed in. I actually had one fail, which Aqueon replaced (as Aqueon heaters are guaranteed for life as long as you have the original sales receipt). I then upgraded to the Finnex controller. Now in my case, I cranked the heaters up and let the controller control the tank temperature. This worked fine, Then later, I upgraded to the 500w titanium heater.