Salt in ponds

[Russ Little Pond]

I have a question regarding salt and whether a trace of 0.1% salt should be in a freshwater pond ?

The videos I have been watching offers no real evidence as to why its needed other than that its a mineral and it help.

[Manky Sanke]

Russ,

Adding any significant amount of salt to a koi pond would be changing the water salinity in which magoi have evolved. Magoi are the "ancestor carp" from which koi, as we know them, have been bred. Carp kidneys have evolved to expel a normal amount of urine, much of which is due to the water that enters a carp due to osmosis from water with very low salinity. We mess with what nature has designed at our own risk.

That said, carp need to uptake traces of sodium and chloride from their environment.

From the teachings of Professor Richard Strange, in special cells in the gills called chloride cells, carp exchange sodium for NH4. This initially removes ammonia and then the sodium goes on to fulfil several functions in their bodies. In the same cells, carp also uptake chloride to help regulate bicarbonate levels in their blood and to replace chloride that has been lost. These quantities are trace amounts only and, fortunately, there is a trace of salinity in natural bodies of water that is sufficient for their needs.

Since a trace of salinity is normal in natural bodies of water, the water that arrives at our taps also contains a trace of salinity because it isn't removed during purification processes at water supply authorities so this trace will supply all that our koi need if the pond is filled with normally dechlorinated water.

So it's true that a trace of salt is necessary in the koi environment and that salinity is invariably present in the normal tap water supply. The maximum level in water supplies is 0.06% which is more than sufficient for carp.

[Russ Little Pond]

Manky

Thank you for that lad.

Very interesting.