You are making a mistake...water changes 3-4 times per week is the right thing to do. Think of it this way...the filters, pumps, media, air, bacteria etc in your tank function as a giant kidney. Kidneys in Humans filter blood and remove toxins. There toxins are passed from the body in the form of urine and feces. You drink liquids and your body takes what it needs...it disposes of the rest. In the case of the aquarium the waste have nowhere to go. The filters, charcoal, air, bacteria etc all help, but they can't do it alone. There is a lot in your aquarium water both good and bad. The only way to get rid of the bad is through frequent water changes...otherwise toxins build up in the aquarium leading to distress and later disease and finally death in your fish. Think of yourself drinking Vodka all day every day. In no time at all, your body would be full of toxins leading to organ failure and death. are you asking your fish to do the same thing? Toxins are flushed from the body with water. Water hydrates, nourishes, dilutes, flushes and regulates. In your aquarium (kidney) it does the same thing. I do water changes 4-6 times per week....I NEVER have water quality problems or fish disease / death. After over 20 years in the hobby, the one thing I have learned and an absolute....everything goes back to water. Water is where you can do the greatest benefit or the greatest harm.