10-11-2005, 08:00 AM
Join Date: Jul 2005
With my low tech tank, I only just stopped doing water changes with the last one on Saturday. I was reading a book and on a site that was a big proponent of regular and routine water changes. The low tech site also doesn't use filtration though, so water change is the only filtration besides plants. Though reading another site that one of the members posts on, he doesn't do water changes OR filter (but he has a rich organic matter --rabbit pellets-- under his substrate).
My guess for a heavily planted, well-growing low tech goldfish tank that you aren't dosing with EI would be every couple of months do a water change. If you are dosing then you would want to do water changes like Tom recommends to remove excess ferts.