These tanks used filters, substrates and air.  Nitrates and ammonias would rise weekly, and water changes were absolutely necessary.  The substrate would need replacing after about 1 year due to fouling with detritus and rotten plant roots.  The filter would become clogged with detritus and nitrifying bacteria every month.  I no longer have these problems, and can go for weeks without water change as long as I have an abundance of healthy floating plants.  They clean the water beautifully.

Some of my 10g tanks before I went all NFSA on them:

Fish Tanks IV 017 Fish Tanks IV 011 Fish Tanks IV 010 Fish Tanks IV 009 Fish Tank III 016 Fish Tank III 014 Fish Tank III 013 Fish Tank III 012 Fish Tank III 011 Fish Tank III 006 Fish Tank III 005 Fish Tank III 004 Fish & Me 018Fish & Me 006 Fish & Me 005 Fish & Me 004