Running a pump externally?

[Tylt33]

I know this is a pretty basic question, but how do you do it with a non-selfpriming pump? I have three pumps (Mag12, Mag18, Eheim 1260) in my sump right now (skimmer, return, chiller) and they're keeping the tank really hot.

I've never run a pump externally, always submerged. How do you get the flow started if they don't self-prime? Does the pump have to be at an elevation lower than the sump, and then start a siphon? What kind of plumbing do I need (I can't find the original boxes and instructions)? A picture or something would be very helpful!

 

[james3370]

i'm doing a mag 9 on my over the top closed loop & i put a t-fitting w/ a screw-on cap to fill the input side

can be seen on the angled pipe (clickable thumbnail):

 

[scaryperson27]

James. Wow, that's nuts.

Tylt, you have to drill the Sump for a bulkhead that will supply the correct piping for the external pump that you choose.

I would opt for something that you could run a manifold off of easily, preferably a pump that can handle a good head pressure. This is what I did with mine.

I used 1" manifold and reduced it down to 3/4 for the returns, then put in a bushing to reduce the piping to half inch and ran it to my reactor/recirculating skimmer manifold.

If you wanted to elevate your pump above the sump water level, than you would have to put on a check valve to keep the pump primed. Otherwise having the pump below the water level will keep the pump primed.

In your case where you are trying to reduce the water temperature, you would want to have a pump that is air cooled. Stay away from water cooled pumps. With your tank we are probably looking for a pump that will push out close to 1500 GPH.

http://www.aquacave.com/gen-x-pcx-70-external-waterbr-pump-717.html

 

[jdieck]

As far as the pump inlet pipe is submerged the impeller will stay flooded and you will have no priming problems. In other words the water depth in the sump is at least in line with the top of the pump's volute.

 

[Tylt33]

Wow, thank you guys! I appreciate all of the feedback. I think I'm up against a problem though. I designed and had a custom sump built back when I was still really new (I'm only fairly new at this point), and did not allocate any room within my stand for an external pump, not realizing the heat issues with an internal pump.

My current return pump is a Mag 18, and returns water through two overflows to the tank, as well as providing circulation for two small refugiums. I'm wondering if the best route would be looking at a larger, more efficient, submersible pump and have it (in addition to providing return flow and flow through the refugiums) provide flow through my JBJ 1/3 HP chiller, which would then return through one of the overflows. That way I could eliminate the pump that is dedicated to the chiller, and would get one pump out of the sump; I'm worried about having enough flow, however.

Are there more energy efficient pumps that are submersible and provide more flow than a Mag 18? I know Red Dragons are... but yikes at the price! Do all pumps that run off the same wattage produce the same heat (theoretically?)?

Does my reasoning make sense? I'm open to suggestions at this point. My pumps are keeping my tank between 5 and 8 degrees above room temperature so far from what it appears.

Here are some pictures in reference to my sump:

Again, I appreciate all of the great feedback! Thank you!