Mike O'Brien
09-13-2006, 10:52 AM
A sump can really make it much easier to keep a reef tank. But there is a fair bit of confusion associated with how they work. Hopefully I can clear up some of the confusion in this thread.
What is a sump ?
By definition a sump is nothing more then a low area for the collection of water. For our purpose it's usually an aquarium or other container placed under the tank, but it can be anywhere as long as it's lower than the display tank.
One of the more obvious points is that it adds more volume of water to the system. This is good for a few good reasons. First is that with the added volume, temperature will remain more stable. More water in the system means there is more of a reserve of things like calcium and alkalinity in the system, so these parameters will be depleted more slowly. On the other hand the undesirable things like nitrate and phosphate that tend to accumulate in the system will do so more slowly.
The sump gives you room for equipment. The main thing here is the protein skimmer. The fact is that good skimmers are big, if you want to use a good skimmer, you're gonna need a sump. The list of additional equipment for sumps is long. Various reactors are frequently used in the sump, chemical media reactors for running things like activated carbon or phosphate removal media. Calcium reactors, kalkwasser reactors. An important system run on the sump is the auto top-off system. For reasons I'll get into soon the sum is where the water level will change, so this is where you want the top-off system to be. The fresh water is also allowed to mix with the tank water before being pumped into the tank. Additionally any supplemental additives are better added to the sump, especially those that effect Ph, but all additives can be more safely added into the sump.
The sump also makes the removal of the surface scum in the display tank to be removed. This is really important, first because it's waste that you want out of the tank, second it greatly increases the gas exchange which is responsible for keeping the water saturated with oxygen and removing excess carbon dioxide, together keeping the tank's Ph in line.
How does a sump work ?
The sump works by Means of an overflow system in the tank and a return pump in the sump. Water is pushed into the tank from the sump. As the tank fills, water overflows into the overflow chamber and falls back down into the sump.
This causes a lot of confusion at first, but it's really a simple concept when you understand it. The tank can only hold a certain amount of water. Any more added and it's going to spill out. For this reason the overflow will only allow exactly the amount of water provided by the pump to spill back into the sump.
Reef Ready tanks are more popular now. These tanks have an internal overflow system built into the tank. They are basically foolproof and start on their own after being shut off. With this system there is a section, usually in the back corner of the tank with a baffle that has slots cut into the top. As the tank fills water flows through the slots sucking the surface water into the chamber where it flows through the standpipe and into the sump.
here is a pic of the internal overflow with a Durso style standpipe installed.
http://i5.photobucket.com/albums/y157/Mike0101/pics173.jpg
The other type of overflow system is a hang on the tank style. The effect is the same, but with this there are two boxes, one hanging in the tank with the slots for the water to enter and one on the outside that contains the standpipe. A U-tube is used between the two boxes for the water to flow through. They are designed to keep the tube filled with water once running so that if the power goes off and then back on the overflow will start automatically, but at initial startup the air must be drawn from the tube in order for the water to begin to flow. IMO these models are fine to use, but require at least periodic inspection to ensure there is no air collecting in the tube and there is nothing beginning to clog it.
here is a HOB overflow
http://i5.photobucket.com/albums/y157/Mike0101/sm_bend.jpg
The great part about these overflow systems is that the water level no longer fluctuates in the display tank. The pump is constantly keeping the tank full and only the excess is allowed to flow back into the sump. The sump is where the water level will drop due to evaporation. This makes it the perfect place to install an auto top-off system. Most use a pair of float valves or switches to turn on a feed pump when the level drop's and shut it off when it rises back up.
One thing an overflow does that most people dislike is add micro-bubbles to the water. As the water goes down the standpipe air is drawn along with it. Without the air the falling water would create a siphon and suck the water too fast causing a flushing action where all the water is sucked out of the chamber really fast, it sound's just like a toilet flushing. Then it fills again and when it reaches the top it flushes again.
To remove these bubbles one of the more popular methods is a series of baffles. Just panes of glass or acrylic blocking the flow of water.The water is forced to flow over the first baffle and then under the second. As the water moves down, the bubbles will tend to float up to the surface where the pop. The result is clear water after the baffles. This is where you'll place the return pump so that it returns bubble free water back to the tank.
Here is a diagram of my sump which shows the placement of the baffles in relation to the pump.
http://i5.photobucket.com/albums/y157/Mike0101/thesump.jpg
As in this diagram you can create another section between the skimmer and the return pump with additional baffling. This are can be used as an area for growing macro algae or as a refugium for pods. You can read this thread for more info on refugiums.
http://www.reeflounge.com/showthread.php?t=8722
I'd also like to address the placement of the baffles. You'll find that most commercially available sumps and most DIY versions use a different configuration for the baffles. Config A in the diagram. As the water flows over the first baffle, micro bubbles from the skimmer along with bubbles created as the water falls, flow into the next chamber. As the water is forced downward the bubbles rise and clear water flows under the second baffle. Now the clear water flows over the third baffle and falls into the return chamber. As it enters the water in that chamber more bubbles are formed. These bubbles may then find their way to the pump and cause micro bubbles to enter the tank.
In Config B there is one less baffle. As the water that is free of bubbles flows under the second baffle it goes directly into the return chamber where the water is completely free of bubbles. The third baffle is not needed and as you can see it defeats the purpose of the first two baffles.
http://i5.photobucket.com/albums/y157/Mike0101/baffles.jpg
What is a sump ?
By definition a sump is nothing more then a low area for the collection of water. For our purpose it's usually an aquarium or other container placed under the tank, but it can be anywhere as long as it's lower than the display tank.
One of the more obvious points is that it adds more volume of water to the system. This is good for a few good reasons. First is that with the added volume, temperature will remain more stable. More water in the system means there is more of a reserve of things like calcium and alkalinity in the system, so these parameters will be depleted more slowly. On the other hand the undesirable things like nitrate and phosphate that tend to accumulate in the system will do so more slowly.
The sump gives you room for equipment. The main thing here is the protein skimmer. The fact is that good skimmers are big, if you want to use a good skimmer, you're gonna need a sump. The list of additional equipment for sumps is long. Various reactors are frequently used in the sump, chemical media reactors for running things like activated carbon or phosphate removal media. Calcium reactors, kalkwasser reactors. An important system run on the sump is the auto top-off system. For reasons I'll get into soon the sum is where the water level will change, so this is where you want the top-off system to be. The fresh water is also allowed to mix with the tank water before being pumped into the tank. Additionally any supplemental additives are better added to the sump, especially those that effect Ph, but all additives can be more safely added into the sump.
The sump also makes the removal of the surface scum in the display tank to be removed. This is really important, first because it's waste that you want out of the tank, second it greatly increases the gas exchange which is responsible for keeping the water saturated with oxygen and removing excess carbon dioxide, together keeping the tank's Ph in line.
How does a sump work ?
The sump works by Means of an overflow system in the tank and a return pump in the sump. Water is pushed into the tank from the sump. As the tank fills, water overflows into the overflow chamber and falls back down into the sump.
This causes a lot of confusion at first, but it's really a simple concept when you understand it. The tank can only hold a certain amount of water. Any more added and it's going to spill out. For this reason the overflow will only allow exactly the amount of water provided by the pump to spill back into the sump.
Reef Ready tanks are more popular now. These tanks have an internal overflow system built into the tank. They are basically foolproof and start on their own after being shut off. With this system there is a section, usually in the back corner of the tank with a baffle that has slots cut into the top. As the tank fills water flows through the slots sucking the surface water into the chamber where it flows through the standpipe and into the sump.
here is a pic of the internal overflow with a Durso style standpipe installed.
http://i5.photobucket.com/albums/y157/Mike0101/pics173.jpg
The other type of overflow system is a hang on the tank style. The effect is the same, but with this there are two boxes, one hanging in the tank with the slots for the water to enter and one on the outside that contains the standpipe. A U-tube is used between the two boxes for the water to flow through. They are designed to keep the tube filled with water once running so that if the power goes off and then back on the overflow will start automatically, but at initial startup the air must be drawn from the tube in order for the water to begin to flow. IMO these models are fine to use, but require at least periodic inspection to ensure there is no air collecting in the tube and there is nothing beginning to clog it.
here is a HOB overflow
http://i5.photobucket.com/albums/y157/Mike0101/sm_bend.jpg
The great part about these overflow systems is that the water level no longer fluctuates in the display tank. The pump is constantly keeping the tank full and only the excess is allowed to flow back into the sump. The sump is where the water level will drop due to evaporation. This makes it the perfect place to install an auto top-off system. Most use a pair of float valves or switches to turn on a feed pump when the level drop's and shut it off when it rises back up.
One thing an overflow does that most people dislike is add micro-bubbles to the water. As the water goes down the standpipe air is drawn along with it. Without the air the falling water would create a siphon and suck the water too fast causing a flushing action where all the water is sucked out of the chamber really fast, it sound's just like a toilet flushing. Then it fills again and when it reaches the top it flushes again.
To remove these bubbles one of the more popular methods is a series of baffles. Just panes of glass or acrylic blocking the flow of water.The water is forced to flow over the first baffle and then under the second. As the water moves down, the bubbles will tend to float up to the surface where the pop. The result is clear water after the baffles. This is where you'll place the return pump so that it returns bubble free water back to the tank.
Here is a diagram of my sump which shows the placement of the baffles in relation to the pump.
http://i5.photobucket.com/albums/y157/Mike0101/thesump.jpg
As in this diagram you can create another section between the skimmer and the return pump with additional baffling. This are can be used as an area for growing macro algae or as a refugium for pods. You can read this thread for more info on refugiums.
http://www.reeflounge.com/showthread.php?t=8722
I'd also like to address the placement of the baffles. You'll find that most commercially available sumps and most DIY versions use a different configuration for the baffles. Config A in the diagram. As the water flows over the first baffle, micro bubbles from the skimmer along with bubbles created as the water falls, flow into the next chamber. As the water is forced downward the bubbles rise and clear water flows under the second baffle. Now the clear water flows over the third baffle and falls into the return chamber. As it enters the water in that chamber more bubbles are formed. These bubbles may then find their way to the pump and cause micro bubbles to enter the tank.
In Config B there is one less baffle. As the water that is free of bubbles flows under the second baffle it goes directly into the return chamber where the water is completely free of bubbles. The third baffle is not needed and as you can see it defeats the purpose of the first two baffles.
http://i5.photobucket.com/albums/y157/Mike0101/baffles.jpg