Reptile & Amphibian Forums

So from doing research I see that I need/should change the water every week to 10 days or so..Assuming that my ammonia, nitrate, nitrite,pH, ect levels are all good, why do you have to change some of your water? Wouldn't that change your bacteria and other levels making the system less equalized? I'm confused.

Good question. So the reason you have to do water changes every 2 weeks roughly is because your aquarium is a closed system instead of the natural habitat (a lake, river, the ocean, etc.). In an open system the wastes are all replenished with good healthy water, but in a closed system all the wastes accumulate and add up to be toxins. You see, when you and your fish excrete wastes via the anus, your body is getting rid of chemicals that are considered toxic in high quantities. All those toxins build up after a while, so you doing a water change is similar to the rivers adding fresh water to the oceans...generally speaking.
You worry about the bacteria, but just the opposite is true. If you keep adding all those toxins up, the bacteria can also die. Also, the dissolved oxygen levels in water is very low to begin with, so can you image what the levels are after your fish has been taking up oxygen via the gills after say 14 days... pretty low and hard to extract.

Does this answer your question?
-----
Phishie

"An ounce of prevention is worth a pound of cure."