Help me with my heaters

[bblumberg]

The key factor in sizing heaters is how much you need to raise the temperature over the ambient temperature, over what time period and how readily the container (aquarium or sump) transfers heat out of or gains from the environment. The higher wattage heaters will warm the tank faster and to a higher temperature, but you also run the risk of overheating the tank without a good controller. I had a 250 Watt Eheim Jaeger raise the temperature of my 150 g discus tank to 95 degrees F when it failed on. After that, I dropped to 2 x 200 Watt heaters on an Inkbird controller, backed up by the Apex.

 

[BeanAnimal]

Are the rubbermaids touching the concrete in the basement? Concrete will suck out any amount of heat. I'd recommend lifting them up on some pressure treated wood.

You have a lot of wattage in those heaters. My system in a very similar size and configuration runs off of a single 300w heater and it has no issues keeping up.

insulation board would be more appropriate

It takes 1 btu to raise 1 pound of water 1 degree Fahrenheit.
there are 8.33 pounds in a gallon.
1 watt hour = 3.41 BTU

Let‘s call it 300 gallons and 8.5 pounds per gallon.
That is 2550 pounds of water, so ignoring loss to the room it takes 2550 btus to raise the tank system 1 degree F

To take the system (again ignoring losses) from 60 F to 77 F is a delta of 17 degrees or 43350 btus.
That is 12712 watt hours.
OP has 950W of heaters.
So ~13 hours to bring the tank to temperature If there is no heat loss to the room.

Let’s say that the system loses 2 degrees per hour to the room. That is 5100 more btus per hour required, or about an 1.5 hours of heat. So heat gain is only .5 degrees per hour at best.

If we do the calculus (beyond what I feel like typing on an iPad) this system will take 36 or more hours to come to temperature with even modest room losses. The concrete floor at 60 ambient is not helping.

 

[All_talk]

Bean's maths are good reality check, probably going to need more power. You can check the heat loss to the environment by turning off the heaters (once you are up to target temp) and see how fast the temp drops.

BUT, that fact that the Apex power meter shows the wattage cycling without ever hitting target temp makes me think the heaters are bouncing off the internal thermostats. To test, I would crank the internal thermostats all the way up and see if the Apex will regulate the temp at the set point. Once this is sorted out, set the internal thermostats to just above the set point as a safety.

For safety I run dual heaters that are sized so that each one can just barely keep up with the need on a average day. This way if one fails open, or closed, the tank temp with change slowly allowing time for action.