Healthy Aquarium Water

Fish need clean, chemically balanced water to thrive.

How do I care for aquarium water?

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Be sure to check the water temperature in your tank every day.

Shop thermometers

Weekly

Replace 25-30% of the tank with clean water

Test the water's pH, ammonia, nitrite, nitrate, hardness, alkalinity and chlorine

Shop water test kits

Monthly

Vacuum aquarium gravel

Inspect filter; rinse or replace the cartridge, carbon and pre-filter if necessary

Clean away any algae

Remove and clean plastic plants and decorative items

Prune live plants if necessary

Shop aquarium gravel vacuums Shop filter media

What chemicals are in aquarium water?

pH levels

Normal pH range: 6.5 to 8.2

PH is the measure of how acidic or basic a solution is.

Generally, you do not need to worry about pH levels unless your pH levels are dangerously high or low. Most fish can live in a wide range of pH.

If you have elevated levels of ammonia in your aquarium. it will be more toxic if the pH is higher.

Chlorine and Chloramine

Normal results: 0.0 mg/L

Incoming tap water has chlorine or chloramine added to make it safe to drink. These are toxic to fish.

Any time tap water is added to the aquarium, a water conditioner must be used to remove any chlorine/chloramine that is present.

Ammonia

Normal results: 0.0 ppm (mg/L)

Ammonia (NH3) is toxic to fish. It is excreted through the gill membranes of fish, introducing nitrogen into the aquarium.

Ammonia will be converted into nitrite by “good” bacteria.

Nitrite

Normal results: 0.0 ppm (mg/L)

Nitrite (N02) is also toxic to fish. It results from some non-fish waste decomposition (such as uneaten fish food) and natural ammonia oxidation by "good" bacteria.

Nitrate

Normal range: 0 to 30 mg/L

Nitrate (N03) is less toxic, but high concentrations for extended periods of time can harm fish. It is the result of natural nitrite oxidation by "good" bacteria.

General Hardness (GH)

Normal range: 100 to 250 mg/L

GH is the measure of calcium and magnesium ions in water.

Low GH is referred to as soft water, high GH is hard water.

Most fish can live in a wide range of GH, but some species may be more sensitive to changes in GH.

KH, Carbonate Hardness, Alkalinity

Normal range: 120 to 300 mg/L

KH, carbonate hardness, is the measure of carbonates and bicarbonates in water.

Appropriate KH levels will help to stabilize pH levels in the aquarium.

With regular partial water changes using tap water KH will usually remain at a good level.

Temperature

Normal range: 74 to 82 degrees Fahrenheit. (23 to 28 C)

Sudden swings in temperature can harm fish. Use an aquarium heater to keep a consistent temperature