Guys need your help -- Fishtank inflow/outflow rates

  • Context: High School 
  • Thread starter Thread starter Ruckus
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Discussion Overview

The discussion revolves around calculating the inflow and outflow rates of water in a fishtank system that relies on gravity for water movement, without the use of motors or pumps. Participants explore methods for measurement and the implications of flow rates on aquarium management.

Discussion Character

  • Exploratory
  • Technical explanation
  • Homework-related

Main Points Raised

  • One participant seeks to determine the liters per hour from a diagram related to a gravity-fed water system.
  • Another participant suggests that direct measurement is necessary to ensure accuracy, emphasizing the need for empirical data over theoretical calculations.
  • There are inquiries about how to measure the flow rate effectively, with suggestions to fill a vessel and observe the change in water level over time.
  • Concerns are raised about the need for a pump that matches the inflow rate to prevent overflow, indicating a practical application of the calculations.
  • Participants discuss the reliability of systems that use float-operated switches to maintain water levels, hinting at common practices in aquarium management.
  • There is skepticism about the availability of trustworthy formulas for calculating flow rates, with a warning that any discrepancies between inflow and outflow could lead to issues over time.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best method for determining flow rates, with some advocating for measurement while others express doubt about the reliability of theoretical formulas.

Contextual Notes

The discussion highlights the potential limitations of relying solely on theoretical calculations without empirical validation, as well as the complexities involved in maintaining balanced water levels in aquarium systems.

Ruckus
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I need to work out the liters per hour from the diagram I have attached. There are no motors/pumps involved just gravity flowing through a tube. Thanks :thumbs:
 

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Why not directly measure it? You'll have to do that in any case before you can trust any result that you've calculated from your idealized description of the problem.
 
Thanks for your quick reply. How would I go on measuring it?
 
I need to get a pump that would pump the same liters per hour as the tube or the tanks will overflow.
 
Ruckus said:
Thanks for your quick reply. How would I go on measuring it?

Fill the top vessel, measure how miuch the level in the bottom vessel changes in a given time?
 
Ruckus said:
I need to get a pump that would pump the same liters per hour as the tube or the tanks will overflow.

Most reliable and affordable systems use a switch operated by a float to turn the pump on and off as needed to maintain a constant level.
 
Nugatory said:
Most reliable and affordable systems use a switch operated by a float to turn the pump on and off as needed to maintain a constant level.

I haven't yet built it. Its for a rack of aquariums. Is there no formulas to work this out?
 
Ruckus said:
I haven't yet built it. Its for a rack of aquariums. Is there no formulas to work this out?

None that you could trust. Any mismatch between the flow in and the flow out, no matter how small, will build up over time. Have you seen how tropical fish stores handle this problem?
 

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