Internal or External Return Pump Installation

jbassking · Jun 20, 2020

I'm replacing my external Poseidon return pump with a Current eFlux DC Flow pump to help reduce heat. The question is, do I plumb this new pump externally or internally? I know the old pump definitely puts out heat. Since the DC pumps are supposed to produce very little heat, I was advised to put it in the sump.
My tank is usually around 81.5 - 82 degrees. It's a 180g with a 25g sump.
I have 3 ReefLED 90 lights a ReefWave, a powerhead and an internal pump for the protein skimmer.

Maybe I can do it both ways to compare it.

Suggestions?

dbowman5 · Jun 20, 2020

I would put it into the sump. That way any plumbing failure goes into the sump not outside it. the pump is one i was considering and is designed to be submerged so I wanted to take advantage of that. Because of poor vertical lift performance of DC pumps (Current USA discourages the use of that pump for basement sump to main floor DT applications) I have a Vario AC that i put into my sump. It produces only a little heat due to not having a valve controlling the flow while it runs at full speed fighting the restriction like most AC pumps. I am happy with it. the other thing is that i have enough room in my sump for it. if space is a consideration outside could be a better option, I hope you like what you end up with.

ca1ore · Jun 20, 2020

I’d debate the assertion that an internal DC pump adds less heat to the tank than an appropriately sized external one frankly. I have always found most of the heat from an external pump ends up in the air versus all of the heat from an internal one ends up in the water.

jbassking · Jun 20, 2020

I ended up putting it in the sump and the temp is down to 80.0 so far. I also removed the pump for the protein skimmer and put a tee in the return so it feeds the skimmer as well as the return.

mfinn · Jun 20, 2020

If the Poseidon pump is the one I'm thinking of, either way you plumb the new pump should net you a few degrees cooler.
The Poseidon pumps I used to use always added 2-3 degrees. They were silent little pumps, but ran hot.