What Size Aquarium Sump Do I Need? (The Definitive Guide)

what size aquarium sump do i need

This is the ultimate guide to choosing the right size aquarium sump for your saltwater tank.

In this comprehensive guide I will cover:

  • How to choose an aquarium sump
  • Sump vs tank size
  • Types of sumps
  • Sump maintenance
  • And much more

Choosing an aquarium sump for your main tank is a big decision. There are many factors that come into play. Type, size, cost, brand, are all things you need to consider. One of the most common factors you will need to decide on is size. What size aquarium sump do you need for your tank?

I mention in the article do you need a sump for saltwater aquariums, that a sump is not a necessary piece of equipment to have in a saltwater tank. They have huge benefits and I recommend you have one if possible.

An aquarium sump plays many important roles in your saltwater tank. They increase the total water volume of your system, lets you hide equipment for better organization, allows for an auto top off system which helps maintain water level and stability, stabilizes PH levels, less equipment size limitations, provides food sources. Water volume is very important.

Other benefits include:

  • You can incorporate a refugium section into the sump
  • Increases gas exchange
  • Great place for dosing supplements
  • Better surface skimming
  • More flexible and increased filtration

In this article, I will explain how to choose the right aquarium sump for your saltwater tank.

How To Choose The Right Size Aquarium Sump

When making the decision to buy a new sump for your saltwater tank, one of the most important considerations will be the size of your sump in relation to the display tank.

2 important functions the sump tank needs to perform is It needs to have the capacity to hold any tank water that will drain from the display tank and pipes in the event of a power outage or in the unlikely event your return pump was to fail.

The siphon break is what determines this.

The manufacturer of the sump tank will give a tank size rating for each sump. When choosing your sump tank, it’s always best to use the largest size you can. This will give you additional water volume. Also take into consideration how much space you have in your cabinet if that’s where you are planning to place it.

A good rule of thumb is to choose a sump that it 1:3 or 1:4 size ratio. For example, if you have a 120-gallon main tank, you could use a 30-40 gallon sump tank.

A great sump for a 120 gallon tank is the Trigger Systems Sapphire Sump.

If you can afford a larger sump tank and your space permits, then you should consider buying a sump that is rated slightly higher than your main tank requires. There is no harm in having a large sump tank. The bigger the better really. Some of the more expensive sumps will have more features and add ons which are great to have.

Sump Size vs Tank Size – My Recommendations

There are so many different sized tanks in the hobby, it’s impossible to cover them all. But here are some great examples of tank sizes and sumps that are best suited for each one.

What size sump do I need for a 65-gallon tank?

A 65-gallon tank would have the dimensions of 48″ X 18″ x 18″ (or close to it) which is not a huge tank but not small either. If you have this size main tank, there are plenty of sump options for you to choose from.

You could go with the Eshpps Rs-100 which is 24″ x 12″ x 16″ and 20 gallons. Here is my Eshopps Rs-100!

In case you are wondering how to calculate gallons using the tank dimensions, simply multiply the dimensions together and divide by 231.

24x12x16 = 4608 / 231 = 19.9 gallons.

What sump size do I need for a 200-gallon tank?

A 200-gallon tank would have the dimensions of 72″ x 24″ x 28″ (or close to it) so you would need a sump tank of around 50-70 gallons. This is a fairly large size so it’s important to make sure you have suitable room in your stand and proper space in the sump for the equipment you need.

A great sump for a 200-gallon tank is the IceCap 36XL Reef Sump. This sump is 36″ x 23.5″ x 16″ which is 58 gallons.

Aquarium sump maintenance and cleaning

When choosing the right aquarium sump for your tank, you should also consider the amount of maintenance and cleaning it will need. If you have a very large tank of say 250+ gallons, you will need a very large sump tank to handle that size tank.

Regular cleaning and maintenance will be needed regardless of size so although it’s something that you will be able to clean while installed, it’s possible that you will need to remove it from your system periodically. This will make cleaning more difficult.

Routine maintenance includes removing filter socks, changing filter media, cleaning the return pump, reactors, and any other pieces of equipment you have hooked up to the sump.

So depending on how much space you have in your stand and underneath the cabinet, this will play a role in the size of sump you buy. Also, keep in mind that these large sumps are quite bulky and heavy which may not be an option for you when it comes to maintenance.

Large tanks = large sumps.

All in one fish tanks – aquariums with built-in sumps

If you don’t have the option of an external or separate sump tank, an all in one aquarium is something you may want to consider. These are a complete packaged aquarium system with a refugium/sump built into it.

Basically, when you buy an all in one tank, you are getting supplied with everything you need to set up and operate right away. All in one tanks are very modern in design and are ready to operate out of the box. Plug and play with the sump already attached and you won’t need to worry about plumbing an external sump tank.

Hopefully, this guide was helpful and gave you some things to consider when choosing the right aquarium sump size. Take everything into consideration and not just one particular factor. For example, tank size. There are many different items that are worth considering. Once you compare the options, choosing the right one will be an easy task for you!