1. Gravity. Things from up have to go down.
2. Balanced level. Water balances out to one level. Higher "levels" of water will flow to lower "levels" of water until both sides have the same level.
3. Sealed systems. In a sealed system, water will continuously flow as it becomes one mass.
4. Density. It is easier to suck up air (light things) than water (heavy things). If air gets in your system, it is no longer sealed and flowing stops.
All of them are connected so it is beneficial to see how they work together. The first three concepts are essential in making water flow. The last one is important as a fail-safe. For example, if you forget you were draining a tank, not all of the water will be sucked away and your fish will survive. The following images are simple designs that uses these concepts.
My contraption of hoses, switches and Y-joints. These help create a long sealed system and allow water to travel from one end of the fishroom to the other.
The high end draining water from aquarium. Gravity dictates that things from higher places goes down.
The low end flushing water to a pond. The water level (at the end of the hose) will never reach a balanced level with the water where it's draining from. Thus, water continuously flows.
Overflow with net so fish don't escape.
A smaller example. Water drains from a fry tank to a bucket using an air hose.
The draining end uses an airstone to prevent sucking in fry. The airstone has holes all around. The higher holes will suck air and thus un-seal the system and not all the water will be drained.
The draining end.
The filling end. Gravity, Balanced Level and Sealed Systems.
Rubber strips are useful for wrapping and sealing leaks.
I hope you get some ideas about using physics in your fishroom. There are other applications that I have not explored or discovered yet because what you might need may be different from what I need. Apply your ideas to what you find most useful.
Happy Fish Keeping!
EESDA
