Heater Brand Mixing

[TheReaperOfMars]

I am in the process of setting up my new tank, and by total water volume it will be somewhere around 140 gallons all said. I am trying to pick a heater, and I love my Cobalt Neo-Therm that I have on my 29 gallon, but buying 4 150w Neo-Therms seems a bit silly. I am consider mixing and matching a bit to get the best of both worlds in terms of reliability and accuracy.


With that said, has anyone tried mixing Eheim Jagers with Neo-Therms? Specifically, for 140 gallons of volume with a target temp of 78 degrees, and an ambient temp of around 71 in the room what if I did the following:

2 125W Eheim Jagers set to 80 degrees, which should cover heating around 100 gallons of water
1 150W Cobalt Neo-Therm set to 78 degrees.

The goal here would be for the Jagers to stay on all the time and just be a bit under powered for the tank. Then the Cobalt would provide the fine temperature control as it does a great job with keeping the temperature very precise in my experience. My Jagers in the past have kept my tank within maybe a 1.5 degrees of my set temp, and the Neo-Therm keeps my tank currently within a fraction of a degree.


Does anyone have any feedback on the feasibility of this plan?


Thanks!

 

[Quietman]

I had a bear of a time setting up dual heaters without a controller and not have one on all the time. I was also trying to do three - 2 dual and other larger that would control the temp. The amount of fiddling I was doing was insane, so I bought a temp controller (cheap as I'm not overly relying on it). Thought it was a slick idea, just didn't work out during operations the way I wanted. Much happier and feel more secure with what I have in place now.

Happy to share - maybe you'll see improvements.

Original Testing of Heaters

Inkbird setup - end of post

Final design - for now

 

[TheReaperOfMars]

@Quietman Your data is exactly what I am looking for! Some back of the napkin math makes me think for the Eheims you get roughly 1 degree over ambient per 8.5-10 watts on your 45 gallon tank. So on my 140 gallons of water volume I would need something like 25-30 watts per degree over ambient. With my house hovering at 71ish year round, and if I want the Eheims to maintain a temp around 77 degrees, while being set at 80, I would need 150-180 watts of Eheim. I know temperature math doesn't really work like that, so I will have to experiment.

Eheim recommends 1 250w for my water volume. Which is fairly reasonable given that they probably want a margin of error for people that want a cold house and a very warm tank. So 2 75w Eheims, and 1 150w Cobalt would probably give me enough power to do what I want, which is nice, because I already have 1 150w Cobalt.

Am I thinking this will be too easy? I do have an Apex controller, but I would rather let the heaters handle it and have the Apex kill power if it is too much.