You do understand a water change is required like once a week correct?? LOL... You said " if a water change is ever needed" They are needed all the time buddy!!!Water to fill it I will just run a 3/4" ID hose connected to a hose that connects to the shower run it out the window into the back yard into the shed to fill. If a water change is ever needed I will just do the same.
Go read a thread about plant only filtration or an article on aquaponics and leave the o.p. alone. Plant filtration systems are now used for natural pools and even drinking water purification. U guys r pretty dense. Aquaponics systems are self sustaining. I ran one with koi for 3yrs with no waterchanges and no fish casualties....also heavy feedings . Fish create waste, the plants eat the waste and in turn purify the water....simple science. Dont rag on people for using different methods that you may not comprehend.Go look at threads and stickies for the importance of water changes in tropical freshwater tanks. Especially with tanks with large bio loads and heavy feeding.
Not changing the water is essentially mis treating the fish.