Best aquarium sump a product review article including aquarium sump refugium

Aquarium Sump Tanks

Thinking about adding aquarium sump tanks to your display?

This article will help you better understand what aquarium sump tanks, why you may want one, and where to buy them online – with handy product reviews of the best setups.

Table of Contents

Already have a hang on what aquarium sump tanks are and how they function? Perfect, you can duck down to the product reviews with these handy links. But if you’re still getting your feet wet with saltwater tanks, you probably want to read through the entire article.

What Are Aquarium Sump Tanks?

Aquarium sump tanks are vital pieces of equipment that sit underneath your display tank. They contain everything, including your filter, heater, protein skimmer, and other equipment. If you buy a commercially made kit, you’ll probably get something that looks something like this:

Aquarium Sump tank from Amazon, the Aqueon Pro Flex model

Why keep all of your equipment within an aquarium sump tank? Well, other than convenience, obviously. But there are plenty of key reasons:

  • When kept in or on your display tank, your equipment can turn into an eyesore, Keeping it below the tank (and under your stand) keeps it out of the way and out of sight.
  • Keeping the equipment in the aquarium sump tank also provides you with easy access WITHOUT disturbing the living creatures in your aquarium. Then you can perform maintenance or replace anything at any time.
  • An aquarium sump tank also allows you to expand the water volume of your system. This provides your tank with more stability and the capacity to support even more saltwater fish, corals, and other invertebrates without the need for the larger footprint of a larger tank.

To give you a personal example, my current display tank is a 92-gallon (348L) corner aquarium. And my sump tank holds about 16 gallons (60.5L) of water. So my total system volume is around 108 gallons (409L) of water. That’s a SIGNIFICANT increase. And if you want to expand from 55 gallons (208L) to 71 gallons (269L)? All you need is an aquarium sump tank to pull it off.

Aquarium Sump Tank Design

Aquarium sump tank designs follow the same basic patterns, regardless of whether you create your own (more on that in a minute) or purchase a pre-made kit. The design allows for filtration and purification, ensuring your display tank’s water remains healthy and fresh:

  1. Water flows from the display tank down to the aquarium sump
  2. The water flows through a filter sock, which removes large particles and debris
  3. Water then enters the chamber holding the protein skimmer, where it’s skimmed using foam fractionation to remove organics
  4. Space permitting, the water next enters the refugium area, where water receives biological purification
  5. Water then passes through baffles to trap microbubbles
  6. A return pump then pushes the water up to the display tank

Aquarium sump tank design schematic

Sounds complicated, right? Don’t worry; we’ll break down each of the steps (and the individual pieces) next to give you a better idea of what’s happening in your aquarium sump tank.

Filter Sock: keeps sump tank water clean

Typically, a filter sock works as the first filtration step to catch and remove any large particles floating around in the water. You don’t want this debris gumming up the works, so it’s important to get them out of the way FIRST. And that’s what happens with the filter socks in an aquarium sump tank.

Water flows through the socks. Any suspended particles catch on the sock, removing it from the circulation process. Naturally, this means those socks will grow dirty. If you don’t check and replace them appropriately, they could lead to clogs in the system. But since the sump’s easy to access? This isn’t a problem.

Filter Socks Are Your Aquarium Sump Tank Filter

If you have experience keeping freshwater aquariums, you probably wonder what type of filter you need for your aquarium sump tank. But the filter sock? That IS the filter. A filter sock uses fabric or mesh material folded roughly into the same shape as a tube sock. (And that’s how it gets its nifty name)

Filter socks serve as filters in aquarium sump tanks

Filter socks cover the pipes of the water drains into the sump from the display tank. This makes them function as a “sieve” and prevents anything big and bulky from getting through to the rest of your aquarium sump tank. It’s the same principle you’re used to with carbon filters in a freshwater tank.

And you need to pay attention to how disgusting they’re getting if you want to maintain a healthy tank system. Luckily, replacement socks won’t break the bank. (You can’t toss these in the wash as you do with ordinary tube socks)

Protein Skimmer

While filter socks are handy for catching the worst debris that comes through the aquarium sump tank, most reef aquarium hobbyists also install a protein skimmer in the aquarium sump tank. And that’s because a protein skimmer isn’t officially a filter. But it DOES provide water purification.

A protein skimmer is a device that cleans your reef aquarium water using nothing but physics and bubbles (or is it bubbles and physics?). Tiny scrubbing bubbles remove all kinds of nasty stuff from your aquarium. (No, not the kind of scrubbing bubbles you use when it’s time to tackle the bathroom on cleaning day – though the principle is kind of the same)

Protein skimmer placement and function in a reef aquarium sump tank

Technically, you can install the protein skimmer anywhere you want within the sump tank. I prefer to put the protein skimmer upstream of the refugium. Putting the protein skimmer AFTER the refugium means losing skimming off all of the beneficial invertebrates your refugium is producing. (Which means you spent money on an additional component for your aquarium sump tank that isn’t helping you out)

Refugium in a sump tank

Aquarium sump tanks with a refugium are a naturalized part of the setup. Here, impurities are removed from the water naturally by the organisms living in the refugium. (In other words, you have your own colony of living purifiers – which is pretty cool when you think about it)

How an aquarium sump tank refugium works

Many aquarium owners will use the aquarium sump tank refugium when they have deep sand beds.

Deep sand beds are live sand that serves as the home to aerobic (oxygen-loving) and anaerobic (non-oxygen-loving) bacteria. These bacteria act as the waste-processing plants inside your aquarium sump tank and turn ammonia into nitrites, nitrites into nitrates, and then completely remove the nitrates from the system. This prevents unwanted wastes from accumulating in your tank. That means a healthy environment for your marine tank – not to mention a natural cycling system.

In addition to deep sand beds, a typical sump refugium will also have macroalgae (like Cheatomorpha) and other tiny invertebrates. They perform the same handy “sterilization” technique.

It’s also popular to add live rock to the aquarium sump tank refugium to provide additional biological filtration capacity – while providing a substrate for your invertebrates and bacteria to grow on.

Because the sump remains below your display tank (and, thus, away from the predators you keep in your tank), tiny beneficial invertebrates called copepods often live and reproduce there. So if you’re looking to form a beneficial and natural live food for your fishes and corals? A refugium is the best place to do so.


Now we come to the baffles part of the aquarium sump tank. Baffles are narrow walls that force the flow of water over and under the walls, sequentially, to trap the bubbles created by water flow AND the filtration and sterilization processes of the other components. All of the twists and turns serve to remove the bubbles from the water:

  1. Bubbles are forced (depending on your setup; it may be a passive process) under the first baffle due to water flow.
  2. The bubbles remain trapped at the top of the second baffle. Remember, bubbles float.
  3. Bubble-free water then flows out under the last baffle.

How baffles in an aquarium sump tank work

Not all sumps have the same number of baffles, but you can see a general concept in the image above. You don’t want to force TOO many bubbles back out into your tank. They’ll obscure the view on your display tank, for one.

But they can also help modulate the flow of water returning to the tank. If you end up with an obstruction at any point in your aquarium sump tank? (Say, because you forgot to change out those socks) The baffles will prevent a sudden flood of water from rushing back to your tank. You DON’T want that to happen and lead to a flood. So while “bubble control” sounds silly, baffles are also important design features for water flow control.

Return pump

A return pump then sends the water up to the aquarium. After all, you’re working AGAINST gravity. Without the assistance of a return pump, the water can’t get out of the aquarium sump tank. Instead, you’ll end up with a pressure problem, which WILL result in a leak all over your floor, eventually.

DIY Aquarium Sump Tanks

Since the commercially available aquarium sump tank options tend toward the pricey side, many people chose to build DIY aquarium sump tanks. This can be as simple as a 10- or 20-gallon (10-78L) aquarium where water collects and gets recirculated, Or you go as sophisticated as some of the more popular commercial models. You can even add filter socks, baffles, a refugium, and even automatic top-off (ATO) devices.

The advantages of building a DIY  aquarium sump tank are cost savings and the ultimate ability to customize the tank with whatever you might need. The downside is that you have to design it and do all the work yourself. (Depending on your aquarium geekiness? That may NOT be a downside!)

Building your own DIY aquarium sump tanks are projects on their own. But this helpful YouTube video can get you started on the right path:

How To: Build an Aquarium / Fish Tank and Aquarium Sump

Product Reviews

Maybe the DIY route isn’t for you. Not a problem. You can generally find aquarium sump tanks for sale at local pet stores specializing in saltwater aquarium fish. You can also find great options online.

To help you out, I’ve provided product reviews for the most popular models available on Amazon:

ProClear Aquatic Reef Sump RS100

The ProClear Aquatic Ultra Reef Sump RS100 is rated for tanks 100 gallons (379L) or less.

ProClear Aquatic Ultra Reef Sump RS100

Made in America, the aquarium sump tank’s dimensions are 24″ x 10″ x 16″. They use a standard 200-micron bag/filter sock, making replacements easy and inexpensive to maintain over the long haul. This design uses a bubble diffuser tube to remove bubbles. That means lower noise for you to cope with.

Aqueon 34500 ProFlex Sump

Another good option is the Aqueon 34500 ProFlex Sump. This aquarium sump tank is designed to be flexible enough for you to create the sump design of your choice.

Do you want an old-school wet/dry filter? Hopefully not for a reef tank, but maybe you want to use this with a FOWLR or freshwater tank after you’re done. No problem – it’s that versatile.

Want to have a refugium? It’ll handle that addition.

Need to adjust the water height for your protein skimmer? It lets you manage such things without a problem.

The Aqueon ProFlex comes in a few different sizes, depending on the size of the tank you plan to attach it to:

  • 55 gallons/208L with dimensions of 19 7/8 ” x 9 7/8″ x 17 1/4″: Model 1
  • 75 gallons/284L with dimensions of 29 7/8″ x 9 /8″ x 18 7/8″: Model 2
  • 110 gallons/416L with dimensions of 25 7/8″ x 13 3/4″ x 17″: Model 3
  • 210 gallons/795L with dimensions of 36″ x 13 3/4″ x 18 7/8″: Model 4

Aqueon 34500 ProFlex SumpIf you go with this aquarium sump tank, make sure you watch out for some key problems. Several people who purchased this unit online reported the sump arrived with a crack in it, had broken parts, etc. You should inspect anything you purchase online. But since you will be plunking down a couple hundred dollars for an aquarium sump tank? You’ll want to carefully inspect everything when you receive them to make sure they are defect-free. There’s NOTHING worse than coming home one day to a soggy carpet because your sump leaked.

Another con is that owners reported the filter socks were challenging to remove. (No one likes that)

Eshopps AEO14005 Reef Sumps

The Eshopps AEO14005 RS-100 is designed for simplicity and affordability. Rated for a 75-100 gallon (284-379L) aquarium, it’s a great option if the space is limited in the stand under your display tank.Eshopps AEO14005 RS-100 aquarium sump tank

The dimensions of the Eshopps AEO14005 RS-100 (according to the manufacturer’s website) are 24″ x 12″ x 16″. The protein skimmer compartment is 9″ x 11.5″, fitted with a 7″ micron bag/filter sock. It also comes with a flexible hose that you can attach to your bulkhead or overflow and a pre-filter sponge that rests between the baffles to help provide biological filtration and dampen the noise of your aquarium sump tank.

It’s quiet, compact, and affordable. Something else to consider is aesthetics. Do you like an elegant, clean look/design?

On the other hand, though, if you have space for a larger aquarium sump tank, you should select a larger model that will allow for a refugium. If you have a tank larger than 100 gallons (379L) or have more space under your aquarium to fit a 30-inch or 36-inch long sump, consider getting the Eshopps 14010 RS-200 or Eshopps 14015 RS-300 models.

Keep in mind, though, Eshopps wants you to buy the proprietary filter sock. That’s challenging as you won’t be able to generic.

One thing I love about the Eshopps reef sump is how quiet it is. But Don’t take my word for it. Watch this YouTube video with your volume turned up:

How quiet is the 3rd Generation Reef Sump

If you want to make sure it’ll fit in the space you’ve allocated for your aquarium sump tank, here are the ratings and dimensions for each of the models:

  • 14005 RS-100: Aquarium 100 gallons (379L) or less. Dimensions of 24″ x 12″ x 16″
  • 14010 RS-200: Aquarium 125-225 gallon (473-852L). Dimensions of 30″ x 12″ x 16″
  • 14015 RS-300: Aquarium 225-300 gallon (825-1136L). Dimensions of 36″ x 14″ x 16″

Best Aquarium Sump Tank Review

Looking for the best aquarium sump tank for your reef tank? I’m happy to supply a recommendation based on my personal experience.

Proclear is always an option, But there aren’t many reviews, which makes me a bit nervous.

I was initially attracted by the flexibility of the Aqueon ProFlex design. I liked the idea of standard accessories and ways to change things up. But there are minimum requirements (for me) when looking at an aquarium sump tank setup:

  • It can’t leak
  • Has to be easy to maintain
  • Difficulty getting the filter socks out

Throw in the fact that many of these sumps are reported to have arrived cracked, and it leads me to skip that one.

For me, the best blend of attractiveness, simplicity of design, and functionality are the Eshopps Reef Sumps.

To get the best functionality, you’ll want to pick the largest model that will fit under your aquarium.

My Recommendation for Best Aquarium Sump Tank

Eshopps AEO14005 RS-100 is my recommendation for aquarium sump tank

For More Information

Hopefully, you found this information on aquarium sump tanks helpful. If you are looking to set up your reef tank with the best equipment and gear, you can continue the journey here:

What do you think? Would you like to add a recommendation for aquarium sump tanks you prefer? Please leave a comment below if you do.






3 responses to “Aquarium Sump Tanks”

  1. David Ross

    Hi all, I’ve been a marine aquarium enthusiast for about a year, but only recently had a company in town setup a Bashea 30″ system, along with a powerful protein in sump skimmer and an eshopps evaporation filler. My primary media is my socks of course, carbon, but also a variety of seachem products I love, including denigrate, matrix,their phosphate remover, and their Purigen product. A fixed rate return pump finishes the setup.

    I had to have an overflow box install, as my tank is not plumbed.

    Challenges so far? Getting the in flow rate and out flow rates to always be in balance, and to protect from overflows by keeping the levels in both the main tsk and sump set properly. Still a bit tricky . I added a ball valve after the return pump a few days ago and with some tweaking, I think I’ve go it.

    No space set aside for a refugium right now, but I think I could allocate space for it.

    Questions to the pros ..

    100, 200 or 300 micron socks? Felt or not. Some slow the flow like crazy and the felt ones are almost impossible to get clean but hold up well. Recommendations?

    I’m new to the Bashea brand. Any thoughts on the quality ? I just trusted the vendor.

    Finally, anyone feel my media choices are newbie crazy? Finally, should I switch to a D.C. adjustable pump? Is slowing the flow of a ac pump going a bad idea?

    1. Thanks for the comment, David, and asking for feedback from the community. I’m curious to see what others say in response.

  2. David Ross

    Correction …de nitrate product, not denigrate.

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