my tanks are fully planted with easy growing low light plants , they use up the nitrate and phos, and keep the tank water great . without many plants you do indeed have to do more changes than i do , also i feed very carfully useally frozen foods ,there is little waste ,and i genrally run enough filteration to filter the tank twice over and each tank has only 1 pair or a small group of channa in each ,
before i went with live plants i did indeed have to do more frequent changes though as nitrate level would get very high if left for too long .
cheers col