The water in your fish tank may look clean, but stir the gravel or substrate and you’ll see a surprising amount of debris. Just like your home needs a weekly house cleaning, your aquarium needs scheduled water changes.
The build up of food particles, fish feces and other detritus in a tank creates an unhealthy environment for your fish. Higher nitrate and phosphate levels can also stunt fish growth and promote algae. Replacing the tank water is the best way to avoid this kind of build up and keep your fish healthy.
Full or Partial Water Changes?
New enthusiasts may think they need to empty the tank for a good cleaning, but that’s too stressful for fish. Partial water changes are recommended instead. In fact, changing smaller portions of water more often provides the best results, especially if your tank is small and well stocked.
How much water?
A rough guideline is to replace ten to twenty-five percent of the tank’s water at one time. Keep in mind that topping off the tank with new water isn’t the same as changing it. You may be replacing water that evaporated, but the waste is still there.
Replace water every one or two weeks. For smaller tanks, weekly water changes are best. Bigger tanks or those with less fish and plants can last for two weeks, but you shouldn’t let it go for longer than that as the water quality will deteriorate.
Tips for Changing Water
- Let the new water age before adding it to the tank. To do this naturally, let it sit for a day so gases dissipate. To do this chemically, use a treatment to instantly age and dechlorinate tap water.
- Make sure the new water is the same temperature as your tank water (or within two degrees Fahrenheit) to lessen the stress on your fish.
- Try to shoot for small shifts in your tank’s water chemistry with each change. If your pH shifts more than .2 units, replace less water next time.
- Clean or vacuum the gravel to get rid of some of the detritus. If you do this, don’t clean the filter the same day as this would remove too much beneficial bacteria. Wait a few days to clean the filter.
- Don’t forget to unplug the water heater, which can crack if the water level drops too low.
As you change water more often, you can tweak the amount and the frequency for the best results. With practice, you’ll become a pro at maintaining a clean, beautiful aquarium.
Ready to start? Get your aquarium maintenance tools from Pet Supermarket.