This is not always the case. Moreover, not always does Vitalik, functioning under the active marine aquarium, make a sump above the main aquarium in the café. Also, many have sump volumes that exceed the volume of the display aquarium. There is no point in complicating things, providing calculations and rules. A sump is a container for equipment. Filtering, purifying, adding, etc. An algae filter or one with bio-balls can be called filters. External, hang-on, or built-in, but still a filter.
Tammy
Absolutely right, the location of the "samp" is chosen arbitrarily: above, below, to the side. I provided a classic scheme. Wherever the "samp" is placed, it should work as I mentioned before. The calculations are provided for better understanding. After all, we have beginners among us.
Spencer7805
The main calculation is to ensure that the water drained from above, when the pump is turned off, fits into the sump; the rest is a flight of imagination and engineering thought.
Amanda5586
Another important calculation is that in case of a drain blockage, the water pumped out of the sump should be placed in the aquarium.
Laura3673
For such a case, an additional (emergency drain) is made, which is slightly higher than the main one. In normal conditions (when the main one is functioning (not clogged)), the emergency drain remains in a (dry) state; in other words, since the emergency drain almost never operates, it is always in working condition. It wouldn't look very nice to have an aquarium that is, say, 10 liters short of water, just in case an emergency occurs and water from the return compartment needs to fit in it, and the pump will quickly fail if it runs dry.
Catherine
Why does everyone talk about the bottom and discuss the topic of the sump from the bottom, while there are options for sumps or sump-like systems from the side or back of the aquarium, where there is no risk of overflow, and they work just as well?
Erin2730
Well, the underfilling in a marine aquarium is definitely significant; there needs to be space for the wave somewhere. If it's a couple of centimeters taller, it won't visually affect anything. It's not like Amano's planted tanks, which are filled to the brim; that's really beautiful. Not everyone has a spare hole for an emergency drain, and some don't have any at all. And even if they do, you never know what might happen; anything can occur.
Wesley
Not everyone has the opportunity to place a sump next to the aquarium; in reality, this is very rare. Usually, it is either below or somewhere in the fish room at an arbitrary level.
What is "samp"? (regarding the correctness of terminology)