Submersible return pumps

[MissT]

It's all about preferance and it's also situational. If heat isn't a huge issue, go with a submersible. There aren't many external pumps that are as affordable for the size tank you have. If it was a 100 gallon plus, it might be a different story, but you're looking at like a Mag 9.5, which shouldn't give you any serious heat issues unless you're combining it with metal halide lighting, and no ventilation fans, etc.

[Belowh20]

Mag drives are good pumps at a decent price. One thing I would look into if you decide to submerse one of these pumps is replacing the metal screws on the pump housing with nylon screws. The metal more or less will start to rust over time and its just a good safety precaution to keep it out of your tank.

Another thing you might want to consider is plumbing the outside diameter of the pump, instead if the inner fittings. You probably won't run into the problem on a mag 9.5, but if running a larger mag they will sometimes build up enough pressure to act as an injector nozzle and fill your tank with a nice bubble cloud.

Eheims are rock solid, but somewhat pricey and not so adaptable.

[alton]

Custom Sealife made the T1 through T4 and now someone bought them out. I believe Jason carries these. They heat your water 2 to 4 degrees warmer than with other pumps. So why would you use a pump like this? Because there is no noise! If you have an office and the temp stays at around 70 degrees it is the best pump you could find. My boss has had his for seven years with not one problem and since he is so picky it is perfect because no noise. Panworld pumps are made by an ex-engineer of Iwaki's, but are better. Also when you use a submersable pump you are adding voltage to your tank, so will have to install a grounding probe.

[dow]

Another thing about the Mag pumps... You can easily plumb them external if you want to. I've got a Mag 18 on my closed loop, and it works great.

Of course, I should have left more room behind the tank so it would be easier to get to. That's something to think about if you do plumb one external. You need plenty of room around the pump to work the valves and unions in order to remove the pump for cleaning. Next time there'll be more room and less skinned knuckles.

[theedprado]

I use 2 mag 7s on most of my tanks, one for each overflow. This way if one pump goes out I have a back up. I Like the Iwakis, but they are a little expensive, 3 times the cost of the two mags.

[caferacermike]

Eheims are also able to be plumbed external. I'm a huge fan of Eheim. I have probably about $6,000 worth of their equipment. I bought a Sequence Dart to try out as my first external.