I know this has been asked, but I can't find the topic. How does a sump work? Is it it's own filter? Do you put the heater/protein skimmer in the sump to pump back clean and heated water? I'm getting a 30 gallon sump and I have no idea how to use it
How does a sump work?
Is it it's own filter?
Do you put the heater/protein skimmer in the sump to pump back clean and heated water?
Gauge said:Okay, first thing is the overflow cup. There are at least two types of overflows that I am aware of. The first is like mine, and I will explain it in a moment. The second is a type which overflows basically directly into the sump. The water overflows into a cup with a prefilter and then goes directly to the sump. These usually require a bit of tank modification, specifically drilling your tank.
Now, onto the type of overflow that I have, and most likely the kind you will have. This consists of two cups. One is inside the tank, and the other is outside. There is a "U-Tube" between these two cups. The water overflows from the tank into the cup that is inside the tank. The level in that cup rises, obviously, and then is higher than the level of water in the cup outside of the tank. The U-Tube is a siphon and it works to keep the water levels equal, so when the cup in the tank has its water level go up, the siphon then (through gravity) moves the water over to the cup outside of the tank. That cup, however, has an overflow of its own which lets water flow down a hose and into your sump.
The genius of this plan is that when the pump is turned off, both ends of the U-Tube siphon are still under water, so the siphon does not run dry. It simply stops moving water because the water levels in the two cups equalize.
Here are what the different colored lines represent in the first picture...
RED - Water levels in each cup and the disparity between them which causes the flow through the U-Tube
BLUE - The flow of water
GREEN - The ends of the U-Tube (which you can't see very well in the picture) which will both be under water still when the pump is turned off and the water stops overflowing into the cup inside the tank.