return pump selection/ flow chart

[Kim79]

Firstly, sorry as I know this kind of question has been asked a lot, but I couldn’t find exactly what I was after so here it goes. I am returning to fish-keeping after a long time and don’t have much experience with the sump setup. I was looking at this forum and other resources for information for a little bit.

I have roughly calculated the head pressure as described in the Technical Info section/tab here (https://www.tropicalmarinecentre.com/en/biosystem/filtration/equipment/pumps). But they have this example flow graph for a pump with an ideal range of operation with no explanation of how that is calculated. Chatting online with them they said that if a pump is run outside the optimal range for a long time, it could possibly get damaged.

Any help as to how this ideal range is calculated from the flow chat. I am just trying to understand this so that I can get a pump and run it at as lower power as possible for noise reduction and future use in a bigger tank thanks for the help and happy fish keeping.

 

[Doctorgori]

the chart might be sorta over thinking it….
what size is your tank?
whatever you decide, get a dc pump

 

[DCR]

It is generally determined by the pump manufacturing through testing. There is no way you can calculate it. Theoretically running back on the curve to the left leads to internal recirculation and possible overheating and wear. Running out to the right on the curve can lead to cavitation within the pump which can also lead to damage. The central area is also normally the area of highest efficiency. This is typically a concern with large industrial sized pumps. I would not think it would matter for most hobby pumps although the pump curve you show would be a small industrial sized pump. Not sure if you are really considering this large of a pump.

 

[Kim79]

Thanks for the reply guys. My current tank is small, as it was given by a friend who was not using it. I am going to replace it at some stage with a bigger setup so trying to keep things a bit flexible like getting a sump a bit bigger than required currently and so on.

For my current tank and the rough head pressure calculations, 4000 litres per hour will be just fine. The reason I looked into this was that if it does not have any negative effect instead of having a smaller pump running at 40-60% of its full power I can get a larger pump and run it at around 20-30% to get similar water turn over so that the pump might be more useful in the future.

Keeping the flow in the middle of the pump flow curve was the original idea but when I saw this graph out of interest to understand things I tried asking the question on the web live chat/support and they totally ghosted me :). Thanks again