Heater Options - Balancing out wattage between two heaters

[Doc_]

I am buying new heaters for my new 100.3 waterbox and am after some opinions. 

 

I've made he decision I'm not going to throw my money into one "high end" heater like a Schego and instead go for two Aquael Platinum or two Eheim heaters for a degree of redundancy both of which I have had good results with over the years with my freshwater tanks.

 

The question I have is around sizing. Based off Eheim sizing a 150watt heater is good for between 200 - 300L but based on Aquael's sizing I'd need at least 200watts with 250 having me in the sweet spot of being in the middle of the recommended wattage for my size tank.

 

What I would like to achieve is two heaters together being enough to happily heat my tank without them needing to run full time all the time. At the same time I want to ensure that should one fail in the on position it doesn't overheat my tank which I intend on protecting against with a separate inkbird for each heater. At the same time if one fails in an off position the other should be able to slow down the temperature drop allowing me to respond to the failure and replace it with one I'll keep on standby.

 

If both fail in the on or off position well I have to rely on the inkbird to turn them off and if both fail at the same time I'll have to rely on separate monitoring to alert me to the drop in temp. 

 

Where I live is fairly warm so on the coldest day of the year I don't expect the units to need to push up the temp much more than 15 degrees Celsius to stay above 25 degrees C. Though for 90 % of the year significantly less 

 

Thoughts , opinions and experience would all be appreciated in helping me make my decision 🙂

 

 

[seabass]

Sounds like more fail-safes than necessary, but your plan should work fine.  I'd just get a decent heater and put it on a controller.  However, having a spare on hand is always a good idea. 

 

4 hours ago, Doc_ said:

The question I have is around sizing. Based off Eheim sizing a 150watt heater is good for between 200 - 300L but based on Aquael's sizing I'd need at least 200watts with 250 having me in the sweet spot of being in the middle of the recommended wattage for my size tank.

The difference in sizing is likely due to assumptions of room temperature versus desired tank temperature.  Glass versus acrylic walls, and even a top can make a difference in heat loss.  I suppose that humidity can also come into play.

[mcarroll]

19 hours ago, Doc_ said:

Thoughts , opinions and experience would all be appreciated in helping me make my decision 🙂

Overthinking it, which is OK.  👍

 

IMO the Inkbird adds a set of new failure points, but does almost nothing vs existing failure points.  Not a good add to the system IMO.  Better is to do good design and be there for the tank every day.  (Leave the BandAids to Johnson & Johnson.)

 

Use one right-sized heater per tank of water.  Simple!  No added worries from using a large heater.  No worries about return pump failure cutting off the heat.  No worries about false readings from an Inkbird. 

 

That means if you're running a display with a sump that you run one small heater in the display and one small heater in the sump.

 

Worrying about both heaters failing at the same time in the same way (ON) is too much worry IMO.  You may as well worry about hitting the lottery by accident at the same time you're being hit by lightning.  😉

[Doc_]

Thank you both very much for your advice and insight 😊

 

I agree planning for two failures in the same scenario is quite overboard which is why I haven't bothered. Though I have certainly had some heaters fail over the years and want to make sure I cover my bases. 

 

I'm a little surprised on the suggestion to not use an inkbird , I agree it's something that can fail though the chance of it failing as well as the heaters built in mechanism isn't a very likely event much like the two heaters failing on. 

 

I wonder why you don't recommend I put one in for each heater ? I have to say from heaters to heat mats for reptiles I've not run a heat source without one or an equivalent for a very very long time