The rule of thumb is a 20 to 25% water change once a week unless your water readings with your test kit tells otherwise.What I mean by this is if your readings show ammonia or nitrite or to much nitrate then you will have to do large water changes everyday until your reading are back to were they should be.I do 50% a week, I keep plants so I'm not a fan of algae so I like doing large water changes to get rid of biofilms and other insoluble fish wastes, so algae can't get a foot in the door.
The reason truck is doing 50% weekly water changes is because he has plants and is dosing EI (estimated index) macro ferts.The rule of thumb is a 20 to 25% water change once a week unless your water readings with your test kit tells otherwise.What I mean by this is if your readings show ammonia or nitrite or to much nitrate then you will have to do large water changes everyday until your reading are back to were they should be.I do 50% a week, I keep plants so I'm not a fan of algae so I like doing large water changes to get rid of biofilms and other insoluble fish wastes, so algae can't get a foot in the door.