How to Cycle an Aquarium

How to Cycle a Saltwater Aquarium

You’ve finally decided to dive into getting your first aquarium. The excitement is there and all you want to do is throw some sand, rocks, water, fish, and coral in, sit back and enjoy. Before adding any livestock to a new aquarium, you must cycle the tank to ensure a safe environment for all fish and corals. In this article, we will go over what the nitrogen cycle is and how to cycle a saltwater aquarium.

What is the Nitrogen Cycle?

The nitrogen cycle is the process in which bacteria convert ammonia into less toxic nitrite. Additional bacteria then break the nitrite down into even less toxic nitrate. Regular water changes, combined with protein skimmers and other filtration methods, are then used to keep nitrate levels in check.

How to Cycle an Aquarium

How to Cycle a Saltwater Aquarium

The three most common methods for cycling a reef aquarium are (1) With Fish, (2) Without Fish, and (3) Bacteria Starter. Before starting the process, please make sure you have ammonia, nitrite and nitrate tests, as these will be used regularly throughout the cycling process.

Option 1: With Fish

Cycling a tank using a fish is probably the most common method of cycling an aquarium. However, it needs to be done with caution as ammonia and nitrite reach toxic levels, which can kill even hardy fish. One or two small fish is all you will need for most small to medium-sized tanks. Many people prefer to use damsels, chromis, or clownfish because they are readily available, hardy, and cheap. However, damsels, chromis, and even clownfish can be aggressive to other fish, especially in smaller tanks.

Timeline: At least 3 weeks and likely up to 6 weeks

Benefits: Inexpensive

Drawbacks: Takes time and you may end up with a fish or two you don’t want

Option 2: Without Fish

To start the process, you will need to add an ammonia source such as fish food or a chunk of shrimp. As the fish food or shrimp decomposes, it will create ammonia. Alternatively, pure ammonia, which does not contain any perfumes or detergents or surfactants, can be added. As a general rule of thumb, we recommend 5 drops for every 10 gallons of tank water. Once you start to detect nitrites, reduce this to 3 drops a day.

Timeline: At least 3 weeks and likely up to 6 weeks

Benefits: Inexpensive

Drawbacks: Takes time

Option 3: Bacteria Starter

Bottled nitrifying bacteria cycle is the fastest way to cycle an aquarium. Some of the most popular products include Fritz Turbostart, Dr. Tim’s One and Only, or Microbater Start. These products work quickly and can have your tank ready in little time.

Timeline: In as little as 24 hours, although it generally takes a little longer.

Benefits: Fast

Drawbacks: Bacteria levels may not be stable, resulting in increases in both ammonia and nitrite. It is generally safe to add a small amount of fish right. However, we recommended waiting to add coral for at least several weeks until bacteria levels stabilize.

The Testing Process

  1. Ammonia Test: Test daily until ammonia levels start to drop. Once ammonia levels start to drop, begin testing for nitrites while continuing to test for ammonia.
  2. Nitrite Test: Test daily. Nitrite levels will generally rise quickly and then suddenly fall. Once nitrite levels fall, begin testing for nitrate while continuing to test for ammonia and nitrite.
  3. Daily Nitrate Test: Continue testing for ammonia and nitrite until both reach 0 and nitrate levels fall in the range of 0.025 ppm- 5ppm.
  4. Water Change: Once ammonia and nitrite are 0 and nitrate is in the acceptable range, change 10 % of the water. It should now be safe to add 1-2 additional small fish to the tank.

We recommend adding no more than 1-2 new fish per week after your new tank has cycled. When adding more fish, each addition will add more to the bioload and needs to be taken into consideration to prevent any sudden deaths to new or existing fish. Keeping the lights off for the first few weeks will also help prevent algae growth since algae feed on nitrates and light. Regular water changes and the addition of tank cleaners such as snails, crabs, shrimp, and fish that eat algae will help limit algae growth.

Starting an aquarium is an exciting time, and the excitement can make it hard to keep your patience. Correctly completing the cycle will help prevent issues down the road and help you maintain a successful saltwater aquarium in the long run.

For more information about saltwater aquariums, visit the Simplicity homepage here.

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