Aquarium Q&A: How Often Should I Test my Water?

by Melissa R. on April 25, 2012

Water tests help prevent aquarium problems

Water tests help prevent aquarium problems

Q: What water tests should I be performing on my aquarium, and how often should they be performed?

A: Our goal with any type of aquarium is to provide a healthy and stable environment for the organisms that we are keeping. Temperature should be monitored daily and should remain constant. Ammonia and nitrites are very toxic and have to remain at zero. These need to be tested until the biological filtration matures, or in times of change in the system. The pH and alkalinity should be tested weekly and need to remain stable with the use of buffers or CO2 systems.

The remaining tests are a reflection of our maintenance on the system and include the nitrates and phosphates. These tests should be performed periodically, and should give you an indication as to whether or not enough water changes are being performed. When problems with algae in the aquarium arise, these are the first values to look at and may indicate that more frequent water changes are needed. For the reef aquarist, there are many other tests that should be performed to optimize coral growth. These tests are calcium, iodine, strontium and magnesium. Depending on the results, supplements may be needed.

See the table below for acceptable levels of these parameters for freshwater or marine aquariums.


Temperature pH Ammonia
Nitrate –
Nitrogen (NO3)
72-82°F 6.5-7.5 0.0 0.0 < 50 ppm
African Cichlid 72-82°F 7.8-8.5 0.0 0.0 < 50 ppm
Freshwater Plants
& Discus
76-86°F 6.0-7.5 0.0 0.0 < 30 ppm


Temperature pH Specific
Reef 72-78°F 8.1-8.4 1.023-1.025 8-12 dKH 0.0 0.0 < 1.0 ppm
FOWLR 72-78°F 8.1-8.4 1.020-1.025 8-12 dKH 0.0 0.0 < 30 ppm

More Information:

About the author: Melissa is a devoted pet owner with several cats: Kai, Cirrhi & Ritter; and the newest addition, Emme a Nova Scotia Duck Tolling Retriever. Melissa is an avid dog agility enthusiast, and hopes her new pup will someday be an agility champion! She is a Graphic Designer and Project Coordinator for the and websites. She holds a Bachelor of Fine Arts in Graphic Design from Michigan State University and is a lifelong pet lover and owner. See more articles by Melissa R.

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