General Community Tropical

The community tropical tank is the default setup for most fishkeepers: a mix of tetras, rasboras, corydoras, maybe some guppies or a bristlenose pleco. The species in these tanks come from varied habitats, which is both the strength and the challenge of the profile. You need water that doesn't offend anyone rather than water that's perfect for one species.

A GH of 4–8 °dH and a KH of 3–5 °dH covers the middle ground. Soft-water tetras and rasboras are comfortable at the lower end; livebearers like guppies and endlers prefer the upper end. A target of 6 °dH GH and 4 °dH KH sits in the overlap zone where both groups do well. The pH should land somewhere between 6.5 and 7.5, and with a KH around 4, it typically will.

Most community tanks run fine on dechlorinated tap water, and that's an honest statement. Where blended water becomes valuable is if your tap water sits at one extreme (very soft or very hard) or if you've noticed unexplained problems: fish that won't colour up, corydoras that seem sluggish, or a pH that crashes between water changes. Dialling in the mineral profile won't fix every problem, but it removes one variable from the equation.