I guess everyone has different priorities, but cords in the tank are not an irritant to me. I suppose it depends on your preferred positioning of flow. I tend to put mine near the top to create a gyre circulation. Cords are not an issue.
Minimizing noise along with minimizing maintenance and having high reliability are priorities for me. Coupling through the glass is inherently more noisy and difficult to dampen sound/vibration. You don’t have the advantage of water surrounding the motor. Some very smart guys over there have NOT been able to quiet the pump to my satisfaction. I tried a couple times.
Regarding 2002 style prop pump: I used 2002s for years. By far the most reliable and serviceable pump I have ever come across. Truly an outstanding bit of engineering. However, I think your colleagues may be right, it might not be a worth significant investment to develop prop style top mounted pump given today’s trends.
2002s were awesome, particularly for smaller tanks where high water flow rates often meant you had to battle heat issues. The 2002 solved that by providing an external cooled motor. I used a canopy so the large external motor was not visible. Win-Win.
With the development of the prop pumps, you can now move large amounts of water for relatively little wattage so heat is much less of a concern. At the same time, I (like many others) went to an open top tank with hanging pendant light. Now that I don’t have to worry about heat, I’d much rather have the discrete Stream prop pumps in the tank than an external drive prop pump with the motor above the tank.
If the price was right, an external drive prop pump with 2002/4002 reliability would be awesome for propagation systems, in-wall systems, tanks with canopies, etc. The portion of the market that has trended toward rimless, clean lined, minimalist sets-ups will probably not go for it. If the cost was equal or higher than the equivalent Stream 2, I think it would further reduce the interest. The Stream 2’s are not very obtrusive in the tank.
Regards.
