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     Tunze Turbelle Stream II Controllable Pump - Model 6205

Sufficient water flow is one of the most important criteria when designing a successful reef aquarium. Closed loops and power heads (stream pumps) are usually the accepted way of achieving the needed flow. Both methods have their advantages and disadvantages. My personal feeling is that closed loops require a lot plumbing, which means pipes running everywhere, above and below the display tank. Those pipes take up space - and space is always in short supply.

The firm Tunze makes the best stream pumps available, IMHO. Their new model 6205 push out almost 6000 gallons of water an hour! And they are controllable from between 30% and 100% of their capacity. To make it even better, my new Apex controller has built-in control capabilities that make it possible to conjure up very complex and effective flow patterns within the tank.


  • for aquariums from 800 to 3,000 liters (211 to 792 US gallons)
  • flow rate: 5,000 to 22,000 liters per hour (1,320 to 5,811 US gallons per hour)
  • energy consumption: max. 55 W
  • voltage / frequency: 100 – 240 V / 50 – 60 Hz
  • cable length: 5 meters (16 feet)
  • dimensions: diameter 90 mm (3.5 inches), water outlet: diameter 63 mm (1.96 inches)
  • magnetic holder for glass or acrylic up to a thickness of 25 mm (.98 inches)

There are a number of things to like about the Tunze streams. In the advent of a power outage, the pumps can be run from any 10-24V DC power source. A, not to be discounted, advantage. Titanium allow axels, special plastic bearings, and silicone bearings provide a very silent operation with little wear, over time.

The "ball" design provides a very large intake area which tends to increase efficiency and, at the same time, reduces the pumps tendency to clog up with debris,etc. The newly designed harness allows a very large directional range.

Considering all the plus points offered, I forced myself to look past the price tag, and bought four of these great flow pumps for the display tank:

The new 6205s are quite a bit smaller than the old 6201s and come complete with a mounting magnet rated at a glass thickness of just under 1 inch.

 The power cord is 16 feet long - very much needed when the tank is 8ft long and the cord has to go around a couple of corners!

I really like the new shape. The mount is much stronger than the previous models and holds the pump solidly through the 3/4" panes of the display tank.

The clamp mount is also very robust and allows very smooth adjustment, of the pump, to almost any position.

The power adapter delivers 24 volts, and that at over 5Amps!

The speed adjustment allows a variance between 30% and 100%. I set it at max and let my Neptune Apex do the controlling - works really well.

I've been running the four Tunzes for over a year now. They were four of the first ten to be released in the U.S. - accordingly there were a few minor problems with one of the pumps. Roger, at Tunze, took care of the problems very quickly - some of the best customer service I have experienced.

All four pumps are still going strong, run very quietly, and put out fantastic flow. I must say, I'm very satisfied with the purchase.

11/19/2010 - Tunze recently made changes to the construction of some of their stream models - among them the 6205s.

  • the newly designed magnetic clamp mounts (now called "Silent Clamps" by Tunze) have "rubberized" shock absorbers on the in tank side of the mount - seen in the pics below. They are blue. in color:

    These new shock absorbers go a long way toward completely eliminating any vibration induced resonance being transferred into the glass or acrylic pane where the pump is mounted. This very effectively minimizes any operation noise from the pumps. My streams are now almost completely silent.

  • the drive units have a number of improvements:

    Most important is the new axle. It is now solid titanium. This will solve the problem of corrosion  occurring where bushing cover the axle's surface.

    While on the subject of bushings, they have been redesigned and a attenuation disk (shock absorber) has been added. These effectively eliminate any audible clicks from occurring when the pump undergoes a programmed speed change and the change in pressure pushes the drive magnet back against the rear drive mount.

    The propellers haven't change as far as size and design is concerned, but they are now made of a somewhat more flexible material. This enhances their ability to withstand shock, etc.

    All in all, Tunze has successfully managed to improve an already excellent product.


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