All my levels in my tank are perfect, should I still do a PWC?

Question
Hi Karen,
I have a freshwater tropical tank, I have not done a water change for 15 days and all my levels are perfect no2, no3, ph, ammonia and Po are all nil, or below the minimum color for a reading, using a Hagen master kit. The aquarium is planted and the eheim filter is capable of filtering a tank with 3x the volume. I was just wondering, with everything being well and very happy fish, do I need to change water?? or should I use the " if it ain't broken, don't fix it" rule.
many thanks
Jason

Answer
Hi Jason,
It is always possible the tests -might- be false. Regardless of how many aquatic plants are present and how sophisticated the filtration is - All aquariums should receive regular water changes as part of a maintenance schedule. Its true the amount and frequency of water changes does depend upon the tank's overall environment, the feeding habits of the fish and just how dirty the species may be. For example, you could get by easily with just a weekly 20% water change on a 30 gallon tank stocked with a group of tetras. But that same tank with a single Oscar Cichlid would be quite a sickly fish if you stuck by that regimen due to the oscar's larger bioload.

Even though plants and filtration can take care of some of the water's pollution. They cannot get rid of all the undetectable pollutions that can stunt fish or cause them to become ill. Nothing can achieve what water changes accomplish. And even plants enjoy a water change due to a replenishment of minerals and trace elements in the water. Furthermore water changes help maintain a consistent pH due to replenishing the buffering capacity that with time gets used up by the acidic compounds naturally produced by decaying matter in the tank.

So even though your test results turn out good. I'd still maintain your aquarium with at least a weekly water change of around 30%

Water changes are, after all, the key to success with healthy fish!

Hope this helps!
Karen~