Sera KH/pH-plus 100 ml

A carbonate hardness raiser for freshwater aquariums, 100 ml.

What it does: raises the carbonate hardness to the value you want, precisely and lastingly. The pH is raised gently at the same time and, above all, stabilised.

Why KH matters: most of the fish kept in freshwater aquariums come from relatively hard water. Beyond that, KH acts as a buffer that prevents dangerous pH swings – in particular a rapidly falling pH. The manufacturer's rule of thumb is to keep KH at 6 °dKH or above in community tanks, and considerably higher in special cases such as African cichlids.

Who needs it most: anyone on soft source water. Tap water in many regions is soft enough that the buffering capacity runs out, and acidification then proceeds unnoticed.

Coverage: 100 ml is enough for 600 hardness litres. A hardness litre means raising one litre by one degree, so raising a 100 litre tank by two degrees uses 200 hardness litres. The range has three pack sizes: 100, 250 and 500 ml.