This is a young (1 month) and handsome 13.5-gallon reef tank.

Photo is from the Reef2Reef archives courtesy of @Robg139 ©2019, All Rights Reserved.


This article has been a long time coming. This question is one that is frequently asked to search engines. What do you need to start a reef tank? What do you need to start a saltwater aquarium? What do you need to buy to start a reef tank? What equipment do you need to start a saltwater tank?

It's a tricky question to answer because it's so subjective. There is no one right way to do things in this hobby, and everyone's tank is different. Furthermore, some aquarists are minimalists, and others want high-tech tanks with every gadget.

The biggest problem with an article like this was put succinctly by @Dan_P in my thread about this, "The difficulty in writing such an article is that you are really describing a decision tree not a most likely to be needed list of stuff. What you buy depends on what organisms you wish to keep. That decision heavily influences the designation of must vs nice-to-have’s equipment."

I won't spend time in this article on what the prices are of equipment listed because there are so many variables. You can buy equipment new. You can buy equipment new but on sale. You can buy used through a marketplace like Craigslist, and you can often find used or heavily discounted equipment either through a forum like ours or through a local aquarium club.

For the sake of discussion, I'm going to divide what you need into two broad categories: with and without a sump. Going without a sump is more common in smaller tanks, although you certainly could have a large tank without a sump.

I'm dividing the lists that way because the equipment needed if you have a sump is more and more complicated.

For each of the broad categories, I will further divide the lists into "required" and "nice to have." Nice to have means that you may want it but it's not absolutely necessary and/or it could be added later over time, especially if you're trying to spread out the cost.

After each list, I will explain my reasoning to you. This article will likely engender some debate, and that's okay and to be expected. This is not an exact science.

So, here we go.

This is a more mature (18 month old) and lovely 120-gallon reef tank.

Photo is from the Reef2Reef archives courtesy of @Caliguy1983 ©2019, All Rights Reserved.


Equipment you need to start a reef tank.

Small, 40 gallon or less, without a sump:


1) Tank
2) Heater
3) Thermometer
4) Artificial salt or access to natural sea water
5) Hydrometer or refractometer
6) 1 submersible powerhead
7) Live rock
8) Some kind of mechanical filtration
9) Lighting
10) Water
11) a GFCI (ground fault circuit interrupter) outlet


12) An automatic top off unit (ATO)
13) Protein skimmer
14) Various medications for incoming fish
15) Heater controller that will shut it off if it overheats.
16) RO/DI water
17) Spare heater
18) Spare powerhead
19) Extra tank for quarantine or if a fish gets sick or injured.
20) Test kits
21) Good quality lighting
22) Timer for the lighting
23) Nets for fish if you plan to have any fish
24) Siphon hose
25) Grounding probe
26) Sand
27) If you plan on having hard coral, then eventually you'll need a method for dosing extra calcium

Here are some of the first few things that I bought.

Photo is from the Reef2Reef archives courtesy of @Seawitch ©2019, All Rights Reserved.


1. You have to have a tank or something to hold your inhabitants. As @Mastiffsrule said, a "bucket is acceptable." However, if this is your display tank in your living room, a bucket may not be what you had in mind. How to choose the type of tank you want is a large discussion in itself and beyond the scope of this article just like everything else I've listed here.

2. You have to have a heater, assuming you want a tropical tank. If you want a temperate tank, then you may need a chiller instead.

3. I put thermometer on my list because I think it's important to make sure that your heater is doing what it's supposed to be doing.

4. If you want to have a saltwater tank then you need salt to add to your water or seawater. Some people make their own salt, but I'm not sure that it's cheaper than buying already prepared reef aquarium salt. Remember, there's a lot more to it than just salt--there are a lot of minerals in prescribed amounts to make saltwater that mimics real seawater.

5. You have to have something that measures how salty your water is because you need the water to be at a certain level of "saltiness" and stay there. A hydrometer is cheaper, but a refractometer is more accurate.

6. Flow is critical, so I said "1 powerhead" to create movement in the aquarium. That said, how much flow you need is dictated by what you want to put in the aquarium. Different types of corals require different amounts of flow. This is why you should have an idea what you want in your tank *before* you start buying equipment. Certain types of tanks like all-in-ones (AIO) may have some flow built into the tank because some mechanical filtration is built into the tank.

7. Live rock. By definition, a reef tank has live rock. It's possible to start with dead or dry rock and a small amount of live rock which will, over time, seed the dry rock.

8. Mechanical filtration can be a filter sock or it could be a small, cheap hang-on-the-back (HOB) filter like what is used for a freshwater tank. If you use a HOB filter, then it will need to be cleaned A LOT. Any junk left in the filter creates a nutrient sink that is adding waste to the water column as it breaks down. You want to remove any particulate matter BEFORE it breaks down.

9. Lighting. Okay, sunlight is free. You could use that, but using sunlight comes with its own set of problems. You'll need some real high-quality overhead artificial light if you intend to have coral, especially hard coral like SPS. This is why knowing what you want in the tank before choosing equipment is important. Inexpensive artificial light is fine if you want mainly fish, in what we call a fish-only-with-live-rock or FOWLR tank.

10. You obviously need water. Yes, it's possible to use tap water if you remove the chlorine or chloramine, but you'll have better results if you start with RO/DI water that has zero (0) total dissolved solids (TDS) whether you make it at home or buy it. Many aquarists view RO/DI water as indispensable.

11. A GFCI outlet is important for a saltwater tank. It's important for a freshwater tank, too, but more important for a saltwater tank. A saltwater tank conducts electricity more than a freshwater tank because how well the water conducts electricity is directly related to the concentration of ions in the water.

12. Your tank will evaporate water, and you'll have to top off the tank a lot. An automatic top-off unit takes the guesswork out of it. It's also more important with a smaller tank because it's harder to keep the saltiness of the water at a steady unchanging concentration.

13. Whether or not you use a protein skimmer is up to you. Most aquarists agree that it's important for a reef tank, but more important for larger tanks than smaller tanks. It's also more important if you have a heavy bio-load. Also, if you want to get to a place where you don't have to change a lot of water all the time, then you'll definitely want a skimmer.

14. If you need meds for sick fish, then you need them RIGHT NOW. So, it's a good idea to have some on hand. Many, however, have short expiration dates, so you may not want a lot on hand. If you plan to quarantine fish then you may want at least a few things available to you.

15. Many people believe a heater controller is important even if you aren't striving for a high-tech tank. When heaters malfunction, they typically lock on at a higher temperature that you want that will kill your livestock. It's a good idea to have this safety net.

16. See #10. RO/DI water is very important. Some people would put this in the must-have category.

17. Having a spare heater can be a life saver, literally.

18. Having spare powerheads are useful in case one breaks. You'll also need one for mixing your own saltwater, unless you plan on pulling one out of the tank each time you mix water.

19. If you plan to have fish, and you plan to quarantine them, then you need another small tank just for this. Some would say that you need two extra tanks for this because of a particular treatment called "tank transfer method" (TTM) for treating marine ich. You could use buckets for this, too, or instead. And if you plan to treat with copper then you will need an appropriate copper test kit to go with the copper you purchase.

20. Most reefers believe test kits are very important. Kits that test pH, nitrate, ammonia, phosphate and dKH (alkalinity), for example. There are methods of starting a reef tank, however, such as the Lasse Method, that don't require test kits right away.

21. Good lighting will be essential for certain types of coral. See #9.

22. I include a timer on this list because you want regular photoperiods every day. A timer takes the guesswork out of this.

23. If you're going to have fish, then you need something to be able to move them from one vessel to another, such as in and out of quarantine.

24. A siphon hose is an inexpensive item that does one and only one thing very well: siphon water for water changes. Yes, you can use your spouse's (clean) coffee cup, but the siphon hose is more efficient.

25. A grounding probe keeps you from getting electrocuted. Some would put it on the must-have list.

26. You can certainly have a bare-bottom tank, but some people prefer the look of a sandy bottom, and some creatures need it for digging.

27. Rubber gloves, especially long ones, for safety.

28. Self-explanatory.

Larger aquarium system, 40 gallon or more, with a sump:


In addition to what's listed above:

A) Brute trashcan for mixing saltwater
B) Plumbing parts to connect display tank to sump
C) Pump to move water from sump back to display
D) At least three (3) powerheads total. At least two (2) for the tank + one (1) for mixing saltwater
E) Two (2) tanks total. One is the display tank, and one acts as the sump.

Here are some Brute trash cans that are great for mixing saltwater.


Photo is from the Reef2Reef archives courtesy of @cromag27 ©2019, All Rights Reserved.


E) If you plan to have small polyp stony (SPS) corals which use up calcium for their exoskeletons, then eventually you'll need something for dosing additional calcium. But you don't need this on day one. See #28. As your hard corals grow, their use of calcium will also grow.

F) Sensors to alert you if water levels are too high or too low.

G) Something for emergency power in case you have a power outage.

H) Refugium

I) RO/DI unit to make your own RO/DI water at home

The refugium is an area with typically a lower flow rate where you can grow some macroalgae. Macroalgae adds oxygen to the tank and also removes unwanted nitrate, which is used by the plants. The refugium is also a good spot for increasing your number of copepods or amphipods that some fish may feed on.

For some people the refugium is a designated part of the sump. For others, the refugium is a separate tank plumbed into the system. Depending on the size of the refugium, it can also be used as a refuge for a fish or crab that needs to be isolated from the display tank for whatever reasons.

Keep in mind that the larger the tank, the larger and more costly the equipment will be. A protein skimmer for a 30-gallon tank is much cheaper than a protein skimmer for a 200-gallon tank.

You will also need better quality and higher intensity light for certain types of corals. So, what you intend to put in your tank will have a big impact on the overall cost of your system.

Many people would include different controllers as nice-to-have things for a tank, especially a large tank. However, the choice to automate your tank is very personal and not required to have a great tank. So, I'm not including that in my list.

The nice-to-have list is really limitless. It's nice to have some good reference books and several buckets designated for specific jobs. It's nice to have separate tools for use only with a quarantine tank. It's nice to have a special tool for cleaning your glass. But you can also use an old credit card.

For the sake of discussion, I think this list above gives you a good idea of what's needed to get started. We will publish before long a companion article on the range of prices for everything listed here. There is no limit to what you can spend on your tank if you have an unlimited budget. Most of us, however, have some limits. So, we'll talk about budget next.

And if you're starting out, the absolute best thing that you can do for yourself and your tank is join the Reef2Reef forum. See below.


We encourage all our readers to join the Reef2Reef forum. It’s easy to register, free, and reefkeeping is much easier and more fun in a community of fellow aquarists. We pride ourselves on a warm and family-friendly forum where everyone is welcome. You will also find lots of contests and giveaways with our sponsors.


Author Profile: Cynthia White

Cynthia received her BA in English from NYU a long long time ago. She has been a freelance writer and editor for over 20 years. In 2018, she won the President's Award from the Professional Writers Association of Canada. Now she is a writer and editor on staff at R2R, where her forum nickname is @Seawitch.