FAQ: Is it possible to overdose Seachem Renew™?

Renew™ will never become toxic through overuse, but there are several situations under which it is beneficial to allow some organic waste to build up in the aquarium.  For example, some hobbyists will set up a style of tank referred to as "blackwater", and will intentionally allow tannins and organic acids to build up in the water to mimic a natural tannin-stained environment.  Renew™ absorbs tannins, so  it is not recommended to use Renew™ in this situation.