20 Gallon Saltwater Tank Build Cost – $200 Complete!

20 Gallon Saltwater Tank Build Cost

Are you looking to start up a new 20-gallon saltwater tank on a budget? We all know that the saltwater aquarium hobby can be very expensive. But if you plan things out properly ahead of time, you can really save some money.

This article will prove that you can set up a new saltwater tank without breaking the bank. Here are the things you will need to start a 20-gallon saltwater tank for under $200.

Keep in mind that I won’t be recommending any high-end expensive equipment here, I will save that for another time. But there are some great products that you can use that work well and are affordable.

  • Tank
  • Dry Rock
  • Sand
  • Powerhead or Wavemaker
  • Heater
  • Filter
  • Light
  • Salt
  • Refractometer

Items for a 20-gallon saltwater tank build on a $200 budget

20 Gallon tank

The first thing you will need obviously is the tank itself. This size tank is easily found locally on the used marketplace for $20. Sometimes the pet stores will have new ones on sale for $1 per gallon. But you shouldn’t have a problem finding one for $20. A standard size 20-gallon tank will have the dimensions of 24″ x 12″ x 17″ and a 20-gallon long tank will be 30″ x 12″ x 12″.

Rock for aquascape

stone aquarium rock

To keep the costs down, you should use dry rock instead of live rock. There are some pros and cons of using both which I explain here, but in this case, we want to keep the cost down so dry rock will be the best option. You can easily get away with 20 pounds of dry rock for a 20-gallon tank.

There are also different types to choose from depending on what you are looking to do with it. It’s important to buy a good quality rock that is very porous, allowing it to maximize the beneficial marine life that will grow.

The Natures Ocean Coral base rock comes in a 20-pound box and should cost around $50.


Having sand in your saltwater tank is not necessary, and you may choose to set up a bare bottom tank. Ofcourse,e like everything, there will be pros and cons to having sand in your tank. I like bare bottom tanks on my nano tanks, but the look of sand is more natural and visually appealing.

After your tank is running for a while, you might decide to have a few corals in the tank and some will do better than others when placed on a sandbed. So that is something you may want to consider and choose to have a sand base from the start.

My favorite sand for reef tanks is the Caribsea Fiji Pink. I have been using this for years, and it’s the sand I always choose. It’s available in a 20-pound bag on Amazon.

Powerhead or Wavemaker

Having a Wavemaker in your tank is one of the most important pieces of equipment you need to have in your tank. Powerheads work fine as well, especially in a small tank. I mentioned in the article what size aquarium Wavemaker do I need, that you should aim for a 20-30X turnover rate for water flow in your tank.

Of course, this is not a solid rule that must be followed. It depends on a variety of factors. But to maintain the overall health of your saltwater tank, having proper water movement is crucial.

Keeping the budget in mind, I recommend the Sun Sun JVP-110 circulation pump. This pump will give you the turnover rate you desire in a 20-gallon tank, and it is a reliable pump. I normally wouldn’t recommend a Sun Sun product that is cheap, but I have used this pump myself and had no issues with it. It’s a good little pump.


Maintaining a constant water temperature in your tank is a very important parameter to monitor and maintain. Fluctuations in temperature are not good for the health of your livestock and will cause stress and illness.

The normal water temperature range is between 73-84F with most hobbyists keeping their water temperature at 78-79F. I use the Inkbird temperature controller, which is a very affordable way to maintain the temperature within 1-degree accuracy. I set mine at 79F, and it will turn your heater on and off controller, necessary to maintain that temperature.

When choosing the right sized heater for your tank, you should aim for 5 watts per gallon of water.  So for a 20-gallon tank, you could use a 100-watt heater size. A general rule of thumb for water volume and heater size:

  • 5-10 gallons – 25-75 watt
  • 15-30 gallons – 50-150 watt
  • 40-50 gallons – 100-300 watt
  • 55-75 gallons – 200-400 watt
  • 75+ gallons – 300-400 watt +

The Marineland Precision 100w heater is a great choice.


Proper filtration is important for maintaining water quality and the overall health of the tank. For a 20-gallon saltwater tank, you can purchase an affordable hang-on-back filter that will provide chemical, mechanical, and biological filtration.

There are so many hang-on filters on the market today. Some are better than others with respect to efficiency, noise, quality, and more. I have used many of them and keeping cost in mind, I recommend the Marineland Penguin Biofilter. This filter has been around for a while and is proven to be a reliable and affordable choice.


So the last thing on our list is an aquarium light. I guess you could say light is not really required unless you have corals in your tank, but who doesn’t want a nice light to see your fish? The great thing about lighting a 20-gallon tank is they are very affordable and lighting has improved so much over the past few years, it’s easy to get a good light for a great price.

The light I recommend is the NICREW ClassicLED Marine Aquarium Light. This light will fit a standard 20-gallon tank or the 20-gallon long version. It’s a great light for starting a tank on a budget. It has a great spectrum that will make your fish colors pop.

Now in saying that, I don’t recommend this light if you are planning to have corals, and it’s not a high-end light by any means. But it does a great job lighting the tank and has a controller for different light settings.


Of course, when starting a new saltwater tank, you will need salt. You won’t need the high end or expensive salts when first setting up. If you don’t have corals, you won’t need the reef salt, which comes with elements added.

I recommend the Instant Ocean salt. It has been used by hobbyists for many years and is a good quality brand.


Once you have your tank set up and ready to add the water, you will need to test the salinity to make sure it is within range. You can use a hydrometer which is cheaper, but the refractometers are way more accurate.

I recommend this Salinity Refractometer.

So now that we have listed everything you will need to set up a new 20-gallon tank, let’s check out the total cost to see if we came in under budget.

  • Tank – $20
  • Dry Rock – $50
  • Sand – $20
  • Powerhead – $10
  • Heater – $20
  • Filter – $15
  • Light – $30
  • Salt – $15
  • Refractometer – $15

Total cost = $195!


Do you need a protein skimmer on a 20-gallon tank?

No, you don’t. If you have the option to use one, a protein skimmer can be a very beneficial piece of equipment. But on a smaller nano tank they are not required. You can perform regular water changes and keep up with filtration to maintain a healthy tank.

What type of stand do I need?

Another bonus of having a smaller tank is the fact you won’t need a heavy-duty stand to hold it. A standard 20-gallon tank weighs about 25 pounds empty and close to 200 pounds when full of water. When you add rock and sand, it will be heavier.

You can use a sturdy cabinet or table from home to hold the tank. Just make sure they are braced properly and strong enough to hold the weight. Basic aquarium stands are available online or at the fish stores. Wooden TV stands can also make a good option.

As you can see, you will have no problem setting up a small tank if you are on a budget. If you are just starting in the hobby or looking to set up another saltwater tank, set aside $200, and you will be able to get the necessities to get started right away!