Base load heating a big tank for stability

[Kooma]

I’ve been experimenting with a concept I haven’t see much of, base load heating tank based on its thermal losses.

I have a 225 gallon system and use a 250w and 300 watt Ehiem heater on a Inkbird. My apex backs it up. I was never happy with the range that the Inkbird would heat to, and found the Inkbird can be +/- 1.5-2F off from the apex and other sources. The tank would drift low of the desired temp as per apex and then crank on the heat until it would overshoot the desired top.

I calculated the tanks loss around 68 watts and have added a 50 watt heater with a temp control by the apex to the tank. It’s not enough that it would overheat the system, but recently now that we are in heating season, has kept the tank very stable. Previously I would see swings of 75.8-77.1F when the Inkbird is set to 76-76.5f.

We had a recent heat spell and the tank rose on its own, but it’s been for a few days and I logged in surprised to find a 0.25F swing. INCREDIBLE!

I really want to build out a way to simulate ocean temp changes in an accurate way for coral spawn events and general care. I’d like to do something similar for lighting as well.

Wanted to share some progress :)

 

[Jay Hemdal Verified Community Expert]

I’ve been experimenting with a concept I haven’t see much of, base load heating tank based on its thermal losses.

I have a 225 gallon system and use a 250w and 300 watt Ehiem heater on a Inkbird. My apex backs it up. I was never happy with the range that the Inkbird would heat to, and found the Inkbird can be +/- 1.5-2F off from the apex and other sources. The tank would drift low of the desired temp as per apex and then crank on the heat until it would overshoot the desired top.

I calculated the tanks loss around 68 watts and have added a 50 watt heater with a temp control by the apex to the tank. It’s not enough that it would overheat the system, but recently now that we are in heating season, has kept the tank very stable. Previously I would see swings of 75.8-77.1F when the Inkbird is set to 76-76.5f.

We had a recent heat spell and the tank rose on its own, but it’s been for a few days and I logged in surprised to find a 0.25F swing. INCREDIBLE!

I really want to build out a way to simulate ocean temp changes in an accurate way for coral spawn events and general care. I’d like to do something similar for lighting as well.

Wanted to share some progress :)

Sounds like a great idea!

A side benefit of having two smaller heaters is if/when one sticks on, it is less likely to overheat the tank like a single 500w heater would.

 

[Kooma]

Absolutely, one of the reasons I have a 250 and a 300 on two redundant heat controls (Inkbird and apex).

I am thinking about removing one of the heaters from the Inkbird, the Inkbird just turned on and puts in 550 watts of power which I am expecting to be a spike in the temp, but we will see.

 

[teeeerav]

That looks very steady. How do you have your Apex programmed? Does it just have tighter tolerances for the 50 watt heater and it turns on and off more often than the Inkbird?