Today were going to tackle the topic of filter sumps….what they are, how they work and how to choose the best one for your reef tank.

Filter sumps aren’t new. They’ve been around since the dawn of reef-keeping. Their original function was to provide biological filtration and aerate the water. The early designs worked like this. First, water is drawn from a surface skimmer and gravity drains it down into the sump. The water is then pumped back to the reef tank using a return pump. Bio media would be suspended on a grate and sprayed with aquarium water. These “trickle” or “wet-dry filters” were based on processes that were derived from much larger industrial wastewater treatment plants. The idea was to keep the bio media suspended in the air to maximize the oxygen level for nitrifying bacteria on the living on the media.

Over time, aquarists noticed that if the wet/dry filter was bypassed due to a pump failure or leak, nothing bad really happened. There were no noticeable increases in ammonia or nitrite. That's because most of an aquarium’s nitrifying bacteria live on the rock and sand instead of the biomedia. It was also believed the trickling water would de-gas ammonia out of the aquarium. The idea of degassing ammonia came from an industrial process called “air stripping”. Ammonia could be removed from water by blasting air through a tall contactor as water sprayed over plastic media. The problem is aquariums don’t contain enough ammonia for the process to work. Plus, it requires the pH to be above 10 for the ammonia to be converted into a gas.

So, the question is, what are filter sumps good for? Today’s filter sumps function as a hub for all the important water filtration and automation hardware. With a large enough sump, your equipment options are near endless.

The sump is the ideal place to connect a circulation pump. You can run it submerged or plumb it externally to save space for other hardware. Protein skimmers are a great addition to your sump and will help keep your tank nice and clean. A filter sump also makes it easy to set-up media reactors and de-nitrifiers. You can either use a “T” off of the main water return line or use a second smaller submersible pump to supply water to it.

Sumps give you a place to hide some of your mess and lets you clean up the hoses leading to your tank. The same is true for running chillers. By hooking them up to your sump you can eliminate the need for long unsightly hoses. An automatic top off is one of the key pieces to success in a reef tank as they make sure your salinity stays stable and can give you a chance to relax. Sumps are the perfect location to install your ATO and sumps even come pre-equipped with water level sensors. For high tech reefers, sumps are great for clean installation of probes and other gear.

If you prefer a simpler low-tech setup, sumps are great for just plain old filtering!

Most sumps contain at least one sock filter which are great for pulling out debris before it can break down in your tank. Most sumps also have a number of baffles that channel water flow through the different compartments. The spaces in between these baffles are perfect for placing filter sponges or bags of media.

There's a wide variety of sumps out there to choose from so you are sure to find one that fits your specific needs. Here's what you need to know about picking the right sump for your situation. The first step is to figure out how much space you have available. Measure the width, height and depth of where you are going to place the sump. Don’t forget to measure the size of the opening if you are putting it in a cabinet. It’s important to have enough space above the sump to install a protein skimmer. Double check that you will have enough head room to actually remove the skimmer cup for cleaning.

Once you’ve narrowed down the sump models, it’s time to take a look at the features each offers. Some sumps are made for smaller aquariums and have a lower water flow rating. They provide the most basic features without a lot of extras. Larger sumps have more room to add probe holders, multiple filter socks and even space for a refugium.

When shopping for a sump, look at all the features each model offers. Chances are there’s more than one sump to choose from. Think about the equipment that you have now, but also keep in mind what you may want to add later.

When all the pieces of the filter system fit together, you’ll know which sump to go with. If you still need help deciding on a sump, feel free to send us an email or give us a call and we will be happy to help you out. Don’t forget to like this video and subscribe for more helpful content. As always, take care and happy reefkeeping!



#aquariumsump #aquariumsumpfilter #saltwateraquariumsump