5 important tips to maintain your saltwater tank


Most people believe that saltwater aquarium keeping is infinitely more difficult than freshwater.

Not so. The simple truth is that saltwater fish and invertebrates are not necessarily more difficult to keep. They just happen to have different requirements than freshwater fish and are a bit less forgiving when it comes to mistakes.

The key to having an optimally functioning saltwater aquarium is maintenance. Below are 5 helpful tips that will help you survive the first few days and guide you during the first few months of having your tank.

1. Saltwater Maintenance

The cycling process will undoubtedly be very intense for you and your new tank. You have to content with:

  • Speeding up the cycling process using bacteria starter products
  • Checking for dangerous toxins
This video shows you how easy it is to keep a saltwater tank

Monitoring the Ammonia and Nitrates in the tank

Over the course of the first 4 to 6 weeks your tank will demonstrate the typical cycling process.

During this critical time, you should carefully monitor the ammonia and nitrites in the tank.

  • If the fish look stressed (darting around the tank, gasping for air, or not moving at all), a partial water change might be in order
  • If the fish look very stressed, they may have to be moved to another tank or storage location until the toxicity of the tank is reduced.
  • Keep salt mix and de-chlorinated water on hand for impromptu water changes

Monitoring the PH

Along with monitoring ammonia and nitrites, you should keep a careful eye on the pH.

You should always watch the pH, not just during the cycling process.

The pH will tend to fall over time and needs to be raised accordingly.

The easiest way to raise the pH is through additions of sodium bicarbonate (i.e., baking soda).

  • Mix a tablespoon or so of baking soda in a cup of de-chlorinated water
  • Slowly add it to the tank (over the course of an hour or two. Baking soda will cause a short term drop in the pH, but will bring the pH to 8.2 over time)

Water Evaporation: adding new water to tank

The longer you have the tank, the more water will evaporate from the tank and need to be replenished.

The water that evaporates is freshwater and needs to be replaced with freshwater.

You should never use saltwater for makeup water (unless you want to increase the salinity of the tank).

Cleaning up of Algae

As the tank matures, algae will start to grow (usually around week 2 or 3).

Typically brown algae, otherwise known as diatoms, will be the first algae that show up in the tank.

Brown algae will usually cover everything in the tank and need to be cleaned every week or so.

With time green algae should overtake the diatoms and the brown algae will disappear altogether. If it doesn’t, there might not be enough light for the green algae to out-compete the diatoms.

First Major Water Change

After the tank completes cycling, it will be time for your first major water change.

  • Although the amount of water you change is really up to you, it should be a significant portion of the water. Normally, most people change 40 to 50% of the water in the tank. However, some people choose to change 100% of the water.
  • When changing the water, the gravel should also be cleaned. There are many commercially available gravel cleaners on the market.
  • The chemistry of the change water should be as close to the tank’s water as possible. The pH should be within 0.2 and the temperature should be within 1-2 degrees. It is better to have the change water warmer than cooler (imagine the shock of a cold shower and you will know how your fish will react to cooler change water).

Regular Maintenance Schedule

After the first water change you should establish a regular maintenance schedule. The schedule should include daily, weekly, bi-weekly, and monthly chores.


  • Make sure the equipment is running properly and it does not impact the water
  • Watch your fish during feeding. Behavioral changes are a good indicator of a potential problem which could be attributed to the water


  • Count your fish. In case of fish death, smaller species can decompose quickly, resulting in ammonia and nitrite spikes, and eventually high nitrate levels.

Every Other Week

  • Test your water for vital parameters: pH, carbonate hardness, nitrite, and nitrate.
  • Clean the aquarium walls. Filter floss is fairly cheap and very efficient. Start from the bottom upward and rinse filter floss or scrubber frequently.
  • Vacuum the gravel.
  • Change 10-15% of the water.
  • Rinse filter inserts with the extracted water.


  • Replace filter inserts, cartridges, floss, carbon, and Algone. Rinse entire filter if needed.
  • Inspect tubing, connections, airstones, skimmers and other parts for proper operation.
  • Clean aquarium top to assure your lighting is not affected.
  • Check the expiration dates printed on the boxes and bottles of the aquarium supplies you use. Do not use after the imprinted date. Expired test kits will give false readings and may prompt you to take unnecessary action.
This video shows you how easy it is to keep a Saltwater aquarium as a beginner

2. A Note on Nutrition

Saltwater fish need varied diets.

Constantly feeding your fish flake food may provide it with all the necessary vitamins and minerals, but this may ultimately cause a nutrition deficiency of sorts.

Alternating between cut up shrimp and clam, flake food and frozen/live brine shrimp makes a good combination.

Herbivorous fish, like Yellow Tangs, also like romaine lettuce or Nori (an algae regularly sold at oriental markets) on a regular basis.

3. Using a quarantine tank

Keeping a quarantine tank is especially important for saltwater tanks.

It can be very difficult to treat a sick fish when it is continually being harassed by healthier fish. Also, some medications, namely copper, will kill invertebrates.

You should NEVER put copper into your main tank. Contrary to popular belief, you will never be able to get all of the copper out of the tank.

Also, using copper in a tank which contains live rock will decimate the life forms populating the rock, as most of them are invertebrates.

4. Selecting the best source of water

Source water for saltwater tanks is also very important.

Although the water authority says that tap water is fit for human consumption, it may not be fit for your fish.

Tap water typically contains chlorine and chloramines, which will kill your fish.

Although these will have an immediate effect on your fish, there are usually other contaminates in tap water which need time to affect the tank.

In particular, phosphates will cause massive growths of hair algae and potentially cyanobacteria outbreaks (red slime algae).

Without good quality source water, your tank will not be the continuous joy you hoped it would be.


5. Making sure you use the best purifiers

The best water purifiers on the market are reverse osmosis units.

These, coupled with de-ionizing resins, produce water which is 98% pure.

If the price of a RO/DI combination is too much, then you can always use distilled water (not spring water). However, distilled water may have been stored in copper containers which will kill invertebrates.

Before you start your saltwater tank, find a good store near you.

Good stores will have knowledgeable staff and exhibit a general concern about the care of the animals.

If the store has few saltwater tanks, with a lot of sick or dying fish, don’t buy any fish there, even if they look healthy.