Just trying to understand sump filtration...

[JLad10687]

So here is my basic understanding of how this works.

Essentially, holes or overflow that lead into piping which lead to the sump tank. Once into the sump tank, it goes through the three forms of filtration. Once through the filtration a pump then returns the water from the sump to the tank?

First of all if I'm wrong please correct me. Now my confusion comes from the intial overflow process. What stops the water from overflowing the sump? Is it the pump just pushing it back into the real tank quicker then the sump can fill up? If yes, what happens if the power goes out, even if just for a minute? Does the sump just overflow? Am I wrong about the entire thing? Please help!

 

[cvermeulen]

Well, you could probably find the answer to this with a search, but rather than be a knob, I'll just answer your question...

The system establishes an equilibrium - the sump pump pumps water from the sump until it reaches the overflow. It then continues to rise in the tank only until it's overflowing as fast as the sump pump is returning it. If the overflow is too small, the tank will overflow, if the overflow is too large, it may be noisey, but ultimately nothing dramatic will happen - the lesson being that oversizing your overflows is generally better than undersizing them.

As for the power outage, you need to have enough capacity in your sump such that if the power goes out, the amount of water in th etank that is above the overflow level can drain through the overflow and into the sump, without overflowing it. So, your sump level rises, your tank level drops, until the waterline is below the overflow in the main tank.

This means you must be at least a little careful when doing water changes. If you refill your tank and sump with the sump pump running, you run th erisk of taking up a bunch of your extra space in the sump with water, and having it overflow if the pump stops.

 

[FSM]

If it is drilled, there will be a separate chamber, usually in the corner of the tank. When the tank is almost full, water flows over the top of the edge of the chamber, where the drain is. So, the tank can only drain a half inch of water or so until it drops below the level of the overflow. I turn my pump off during water changes, because taking water out of the tank only lowers the level in the sump chamber.