Join Date: Mar 2007
Location: Hendersonville, TN
Nope, you don't need to! Toxins in an aquarium setting can all be removed based on plant/stock ratios. I promise you that. Minerals can be replenished either through top off or by dosing. If you don't believe me, ask Diana Walsted.
Now, please note that I'm saying that you don't "have to"; I'm not suggesting that you do. But, no, you don't HAVE TO change the water if you know what you're doing.