Water values


Water quality: the basis for all life in the pond

The health of fish and plants primarily depends on water quality. The relatively small amount of water in garden ponds means they are restricted in their capacity to clean themselves. For this reason, the most important water values should ideally be checked once or twice a week.
Tap water should be used for the initial filling and the partial water change.
Rain water is naturally free from hardeners and deficient in minerals and is therefore not buffered against harmful fluctuations in the acid-base balance (pH value). Rainwater should therefore be adjusted to biologically optimum values with Better Water 5in1 before being added.


The most important water values

Total hardness and carbonate hardness

The total hardness (TH) supplies fish and plants with essential minerals. The carbonate hardness (CH) ensures balanced acidity (pH value) and is the most important water value in the garden pond. It prevents a drop in acidity which can be lethal to fish and plants.
Optimum: TH / CH 5-10 °d (German degrees of hardness)
Under 5 °d = too low. Solution: Increase with Better Water 5in1.
Over 10 °d = too high. Reduce with rain water or soft tap water.
If the CH is much lower than the TH, for example, CH = 1 °d and TH = 5 °d, you can selectively increase the CH with KH Plus pond hardener.

pH value

The pH value is a measure of the acidity of the water. The pH has a crucial influence on the health of fish! It is therefore vital that it is regularly monitored and corrected if necessary.
Optimum: pH 7.0 – 8.0 (measure in the morning!)
pH too low or too high: correct with Better Water


Nitrite is formed from the excrement of fish. It is converted into relatively harmless nitrate by special bacteria.
Optimum: Nitrite is not detectable
Measurable nitrite levels could be fatal to fish! Add Clear Water Pond Bacteria FB3 immediately (double dosage). No longer feed. With a nitrite level above 1 mg/l carry out a 50 % water change immediately.


Nitrate comes from the excrement of fish. It promotes vigorous algae growth
and in greater concentrations causes stress for fish.
Optimum: under 10 mg/l
Over 40 mg/l = too high.

Solution:(1) Partial water change with tap water low in nitrate (measure beforehand!)
(2) introduce fast-growing underwater plants
(3) restrict feeding, perhaps decrease the fish population