DawgFace;681857 wrote: Yes the Skimmer companies should be held accountable, the car that gets 12 mph instead of the advertised 24mpg and the milk manufacturer that says 0g of fat when it in reality has 10g. Then maybe some day we can rely that companies are held accountable as I am to keep the trust of friends, family and business relations. But hey maybe that's too much to ask, maybe I should swallow the pill and rest comfortably that deceit is todays norm.
Edit: Tunze BTW did tell thier side of the story, I'll link it in a sec. FYI I got a laugh out of it!
Edit: Tunze official response
Where did we get our flow numbers?
We derived our flow numbers in two ways, by a test termed a “bag test” and by theoretical calculations. The bag test is just as simple as it sounds, a collapsed bag is placed overtheend of the pump and inflated by thepump with water, thetime to fillthebag ismeasured and theflow is calculated. Thismethod has definite limitations,itplacesbackpressureon thepump,and itcannot be used on larger pumpsgiven thelimitsof bag volumeand reliabletiming.Forallpumpsa theoretical calculation is made based on propeller surface area and rotation frequency.
Our bag test results are consistent (within + or – 10% with theoretical results on the pump models 6015, 6025, 6045, 6055, 6065 and 6085. This led us to rely on theoretical numbers. The biggest pump that a bag test can be performed on is the 6105 and the inaccuracy of flow numbers on the 6105 has a different origin than 6205 and 6305 inaccuracies. The 6205 and 6305 flow numbers were only based on theoretical calculations. The 6105, when released, was near specified flow and was bag tested with a result of 90% of theoretical, however, later modifications to reduce noise relied on theoretical flow numbers and flow was lost to these modifications. On models 6205 and 6305 the fundamental issue is that the theoretical flow cannot be reached due to overly constricted intake and output. Going Forward
Over the next 6 months we will perform numerous tests aimed at improving our pumps. We believe pump volume alone does not equal effective flow, the ability to direct that flow is also important. In much the same way as the light available from a bulb means little if it cannot be properly directed into the aquarium,theflow rate at a pump is not as important if there is not sufficient flow at the corals.. We havesincepurchased two flow meters,oneuses comparablesonictechnologyand theotheruses a propeller akin to a common wind gaugeand whilewe havefound thatusing thecomparablemeter and methodology our results are the same. We have also found the propeller based meter gives divergent data, this data indicates that our more forceful targeted flow draws in current as the distance from the pump increases and that our total flow produced may be well higher than the flow of the pump itself. Use of a different methodology may very well give the opposite results, but this does not dispute the results of this study, it will only show that flow is complex and has numerous aspects which we are only beginning to understand. At this point we conclude that the study is correct for the flow produced by the actual pump itself and we will improve the pumps in a retrofittable manner, though this will take time as new parts must be designed and produced. Improvements will be based on increasing intake surface and reducing output restrictions on models 6205 and 6305 and increasing rotational speed for 6105. We would like to thank Sanjay Joshi, Bill Straka and Michael Sandford for performing this study, graciously informing us of the results and giving input on proposed solutions. We believeitisa step forward in uncovering many of the mysteries of high volume, low pressure flow which until recently was nearly impossible to quantify.
