Return Pump Heat: AC vs DC? Or wattage?

Cool Ethan · Jul 21, 2022

So I've been battling rising heat levels in my tank most of this week. Partially due to my air conditioner losing the battle against the actual weather and partially because one of my return pumps has started to falter. As I look for a replacement. one of the keys will be keeping any heat as low as I can.

Does being DC or AC matter?
Does wattage effect things?

Or are either of these negligable not to worry about it when making a choice. Tank is 45g if that changes things.

blaxsun · Jul 21, 2022

Yes and yes. DC pumps will draw less electricity and generate slightly less heat. Whether this will make a difference in your tank is anyone’s guess, though. thanks

Cool Ethan · Jul 22, 2022

blaxsun said:
Yes and yes. DC pumps will draw less electricity and generate slightly less heat. Whether this will make a difference in your tank is anyone’s guess, though. thanks

Thanks, I guess I wasn't looking for anything super specific, but for of a general sense of does this even make a noticeable difference. Basically would a 10 wattage difference really change anything meaningful in 45 gallon tank? Even ~1 degreen would be helpful, but .1 not much.

Tathamet · Jul 22, 2022

I recently changed my return pump which was originally 3.6 watts I think. The new one was 8 watts and I noticed a huge difference with heat output. My fan started turning on multiple times a day (like 4-6 times a day) instead of the original 4-6 ish (maybe less) times a week on the old pump. I ended up switching back. Turned out I had too much flow going through my sump anyway.

edit: my tank is a 9g nano though so keep that in mind.

Cool Ethan · Jul 22, 2022

Tathamet said:
I recently changed my return pump which was originally 3.6 watts I think. The new one was 8 watts and I noticed a huge difference with heat output. My fan started turning on multiple times a day (like 4-6 times a day) instead of the original 4-6 ish (maybe less) times a week on the old pump. I ended up switching back. Turned out I had too much flow going through my sump anyway.

edit: my tank is a 9g nano though so keep that in mind.

Even though its a small tank, knowing 4 watt can still make that much of a difference is still helpful. Thanks.

What do kind of setup do you use to trigger fan? Might have to look in to that

Tathamet · Jul 22, 2022

Cool Ethan said:
Even though its a small tank, knowing 4 watt can still make that much of a difference is still helpful. Thanks.

What do kind of setup do you use to trigger fan? Might have to look in to that

I have an inkbird heating/cooling controller. Can’t remember the exact model. I usually have it set to 78 and when it hits 79 the fan turns on. 77 and the heater turns on (heater doesn’t get too much use unless it’s winter. Even then the room my tank is in runs hotter than the others). The fan drops the temperature 1 full degree in about 20 minutes.

the fan I’m using is out of an old pc and I hooked it up to a cheap 12v power supply I had from an old peltier device project I never finished lol.

edit: just make sure the inkbird is the type that works in water. Some models don’t have waterproof probes

Cool Ethan · Jul 22, 2022

Tathamet said:
I have an inkbird heating/cooling controller. Can’t remember the exact model. I usually have it set to 78 and when it hits 79 the fan turns on. 77 and the heater turns on (heater doesn’t get too much use unless it’s winter. Even then the room my tank is in runs hotter than the others). The fan drops the temperature 1 full degree in about 20 minutes.

the fan I’m using is out of an old pc and I hooked it up to a cheap 12v power supply I had from an old peltier device project I never finished lol.

edit: just make sure the inkbird is the type that works in water. Some models don’t have waterproof probes

Awesome, definitely going to look into setting something like that up.

Tathamet · Jul 22, 2022

Cool Ethan said:
Awesome, definitely going to look into setting something like that up.

Yeah they’re great! I think I only paid $50 CAD for it. It also adds a backup safety for if your heater gets stuck in the on position which seems fairly common. It still turns the heater off since it’s controlled by a separate thermostat. No accidentally cooking your tank!