Maintaining Water Quality and the Ideal Aquarium Temperature

How Best to Manage Your Aquarium's Water Quality

Many factors can affect the water in your aquarium—including the source of your water (municipal vs. spring water, for example), the food you feed your fish, the amount of algae growing, and much more. Below are some common issues and how you can correct them.

Cloudy Aquarium Water

Cloudiness usually results from one of two things: overfeeding/overstocking and “new tank syndrome.”

Overfeeding your fish can cloud your water as the uneaten food decomposes. At each feeding, you should feed no more than what your fish can eat in one to two minutes. 

Overstocking the tank (too many fish) can also cause cloudy water. Excess waste, like excess food, gives off ammonia and nitrites. You should have one gallon of water per one inch of (mature) tropical fish. Have three gallons of water per one inch of goldfish. It is best to buy the largest aquarium you can afford. The larger the aquarium, the more waste your aquarium can handle before it becomes a problem to your fish.

“New tank syndrome” can occur when you set up a new aquarium or when you carry out a large water change. It is very natural for your water to become cloudy as part of the system’s normal biological cycle. The reasons for this are fluctuations in the nitrogen cycle, and the release of gases in solution as the result of an increase in water temperature. A water change of 50% or more will help by restarting the cycle. 

Also, be sure to monitor and change your filter cartridge on a regular basis. A good rule of thumb is at least once a month, or twice a month if you have a heavy fish load or if you have fish that produce more waste, such as Goldfish or Cichlids.

Have a pet store test your water, or you can purchase Tetra EasyStrips™. High ammonia and nitrites would indicate excess food or waste. A 25% water change will bring down these levels until you can fix the problem.

Also, be sure your filter is properly rated for the size of your aquarium.

Green Water

Green water is caused by algae in the water. A few things can cause excess algae:

  • Direct sunlight on the tank. Make sure your aquarium is positioned where this can’t occur.
  • The wrong amount of water in the tank. We suggest you have one inch of fish per one gallon of water. For example, a 10-gallon tank should have only 10 fish that are one inch each. More than this will elevate ammonia and nitrite levels. As a result, the algae will have plenty to feed on.
  • Feeding your fish too much food (excess nutrients). Your fish should be able to eat all the food in two minutes or less.

To solve the problem of green water:

  • Do a 50% water change. Scrub down the insides of the glass with a magnet scrubber or scraper (but please, no soap!)
  • Remove any artificial plants and ornaments, and pour boiling water over them. Wait one whole day, then do a 25% water change. 
  • Cut back on your feeding. This should help get your tank in good shape.
  • Install a UV clarifier. This is installed in-line with a canister type filter that is placed in a cabinet or stand beneath the aquarium. 

Bad-Smelling Water

A bad smell is usually a sign that excess waste is in the tank, and usually excess food.

The first thing you should do is test your water for high ammonia and nitrite levels. To correct the problem, change out 50% of the water, wait one whole day, and then change out 25% more of the water. 

Make sure when you feed the fish that they are eating all the food in two minutes or less. You should have one gallon of water per one inch of tropical fish. Have three gallons of water per one inch of goldfish. Make sure the water is properly filtered as well.

Water Safety

It’s important to treat water before adding fish. AquaSafe® removes chlorine and other harmful substances from the water. You should add eight drops of AquaSafe® per one gallon of water. For example, a two-gallon aquarium will need 16 drops of Tetra AquaSafe®. The 3.3-ounce size has a dropper built into the bottle.

Testing Water

In nature, waste products from decaying matter, fish waste, and other animal waste are naturally filtered. The harmful ammonia and nitrites are removed by bacteria and plant life. The substrate at the bottom of a body of water will absorb harmful chemicals and decaying matter like a natural filter. The actual size of rivers and lakes will keep water healthy for animals. The larger a body of water, the less lethal any harmful chemicals will be to its inhabitants. 

In an aquarium, the natural filtration is replaced by equipment, which filters the water. The larger the aquarium you own, the easier it is to keep the water balanced and healthy. To ensure the ammonia and nitrite levels have not reached harmful levels, it’s important to test the water.

To understand how filtration occurs, one needs to understand the cycle. Fish waste and other decomposing material will produce ammonia. In high quantities, this chemical will kill animals in an aquarium.

A new system will not have nitrifying bacteria present. Ammonia levels and nitrite levels can reach deadly amounts. If this happens, partial water changes will bring levels down without destroying all of the nitrifying bacteria. This will last only about four to six weeks before the tank “cycles.” 

Or, you can add SafeStart® to your new aquarium. SafeStart® accelerates the establishment of the bio-filter in newly set-up freshwater aquariums. The live bacteria start working immediately to provide a safe and healthy environment for your fish without the long wait. SafeStart can also be used after a water change, when adding new fish or after medicating.

Elevated levels of ammonia and nitrite should not occur in a “cycled” tank. Causes of elevated levels in a mature system would indicate overstocking or over-feeding, and should be corrected immediately.

Seek your dealer's advice about the quality of your local tap water. Knowing parameters such as pH and hardness will help you select fish that are well suited to live in the water in your aquarium.

Also ask your dealer if the water in your area contains chlorine or chloramine--strong chemicals used for water treatment in many municipalities. Always add AquaSafe®  to any water before putting it in your aquarium. AquaSafe neutralizes or eliminates chlorine, chloramine and heavy metals. If you have a small aquarium, you may want to consider using spring water, which does not contain harmful chemicals.

Parameter  - in order on strip Ideal Range for healthy aquarium Reason to test Solution Recommendation Dosing Notes
Nitrate Below 40 ppm Waste product resulting from biological filtration that builds up over time. High levels can stress fish and cause algae blooms. Perform a 25% partial water change and add Tetra EasyBalance®. Live plants are also beneficial at reducing nitrate. 1 teaspoon (5 ml) Tetra EasyBalance per 5 gallons aquarium water. If aquarium is 50 gallons, app will calculate and tell consumer to add 10 teaspoons when reading are over 40 ppm.
Nitrite Below 0.5 ppm, ideal is 0 Toxic waste product when good filter bacteria are not functioning. Causes severe fish stress and hinders respiration (noticeable when fish breathe fast and labored). Reduce amount of fish food and conduct a partial water change. Add Tetra SafeStart filter bacteria. Increasing aeration with an air pump and air diffuser is also recommended 1 teaspoon (5 ml) Tetra SafeStart per 5 gallons aquarium water. NOTE, SafeStart Plus can be half dose. Any reading above .5ppm will be 1 tsp per 5 gal and if value is above 3ppm nitrite app should prescribe 2 tsp per 5 gal.
Total Hardness Community fish prefer 50 to 150 ppm depending on species Measures the levels of minerals like calcium and magnesium. Fish like African Cichlids prefer higher levels where Tetras and Discus prefer lower levels. General rule is to let your fish adjust to local tap water and not adjust no action  
Total Chlorine 0 ppm Chlorine and Chloramine is a common disinfectant in tap water and is very harmful to fish gills and invertebrates. Add AquaSafe to all tap water before adding to your aquarium. Also adjust the water temperature to match your aquarium before adding. 1 teaspoon (5 ml) Tetra AquaSafe per 5 gallons aquarium water. NOTE, AquaSafe Plus can be half dose.  
Total Alkalinity Above 80 ppm Measures the levels of buffers like carbonates. Low levels will not adequately regulate pH and potentially cause acid build up or a dangerous pH crash. Perform a 25% partial water change and Tetra EasyBalance. 1 teaspoon (5 ml) Tetra EasyBalance per 5 gallons aquarium water.  
pH - Freshwater Community fish prefer 6.8 to 7.8 depending on species Measures the level of acid and base where 7.0 is neutral. Below 7 is acidic and above 7 is basic. Fish require consistent levels; small changes can be stressful. Perform a 25% partial water change and add Tetra Correct pH® If pH under 6.5 add 1 tablet Tetra Correct pH per 10 gallons aquarium water.  

Aquarium Water Temperature 

  • To make temperature reading easy, consider purchasing an adhesive temperature strip that can be applied to the outside of your aquarium glass. They are inexpensive and available at your local fish retailer.
  • Monitor the sun – Too much sunlight can cause algae growth. If you are installing a new aquarium, place it away from a window. If your existing aquarium is near a window, use a shade to reduce the amount of ambient light.
  • Avoid heat — never place an aquarium above or near a heat source or air conditioner. You want to keep the area’s temperature as stable as possible.
  • For all species of fish, there is a middle ground in which they are happiest, and they must be kept within that range for optimum health. Examples: Tropical fish – 72º - 80º F (optimal is 78º), Common Goldfish – 65º - 68º F, Fancy Tail Goldfish – 65º - 72º F
  • Submersible heaters are the most popular. Some are adjustable and others are pre-set at 78º for your convenience.
  • Be sure to purchase a heater that is properly rated wattage-wise for your tank.
  • Never remove a heater from the water if it is still turned on. Unplug it first, let it cool, and then remove it.
Choose TetraCare for aquarium and reptile support whenever you need it!
Tetra SafeStart – Add fish right away without the need for cycling.
TetraMin – The world's favorite fish food
When your fish needs help, rely on Lifeguard aquarium fish disease treatment.