Closed loop system questions.

[OregonReefer2]

Originally Posted by ChknWing

We started talking about another reefers closed loop and then got off on the topic of mag drive pumps. I use a Reeflo Dart Gold on my closed loop (awesome pump by the way) and I use a mag 12 as the return from my sump. Thanks for trying to set me straight though if I was astray.

I've seen so many people that didn't understand the concept of a closed loop thinking they could plumb it to a sump... Just wanted to be sure you weren't making a fatal error

I use those same two pumps on my system... Love the Dart... The Mag 12 works but when it dies I'll probably replace it with something else... The upside of the Mag 12 is I don't think my heater has ever turned on

[reeflo/sequence]

Couple of things
1-the mag drives and my blowhole pumps are all pressure biased..they pack much more pressure than flow..unfortunately that extras pressure (that you don't need in a closed loop costs wattage..the snapper pump packs lots of flow, low watt and is ideal for closed loops
2- the inttake capapcity should be equal to or greater then the discharge capacity, otherwise cavitation will result as the water-starved impeller will generate bubbles from the water

[sbeason]

Agree with Steve on the math thinking.

You can use a 2" drain and then you can have 4 - 1" returns to your display. The area of a 1" pipe is .785" and for a 2" is 3.14" that is just about a 4:1 ratio. This stand to be true for almost any pipe size combo you could think of.

Typically our returns are smaller diameter than the drains for this mathmatical reason.

-Steve