Bill Stock wrote:
"robv60" wrote in message
ups.com...

would adding potash (muriate of sulfate magnesia, 0-0-22, epsom
SALTS)have the same benefits for fish as adding pond salt to the water?
Or is epsom salts a different breed of salt all together? How much to
add to a 1200g and 1750g pond for floating plant health?



Muriate of Potash is KCL, Epsom Salts (Magnesium Sulphate) is MgSO4+7H2O.
Both can be good for your plants, but neither has any Sodium (Salt). I add
both of these to the aquarium plants and Potash to the pond. Floating plants
also need Phosphate, but I imagine your pond has lots of Phosphate already.



I think the point robv is getting at is with regards to osmotic
pressure, and he is right that adding epsom salts (MgSO4) or potassium
chloride (KCl) would have similar osmotic effects as common salt (NaCl -
sodium chloride).
What I am not qualified to comment on is whether this would do the fish
any good, I am no biologist.
On a point of language, as far as a chemist is concerned (and I am one)
a salt is compound in which there is complete charge seperation, eg Na+
Cl-, it doesn't just refer to common salt. I am just pointing this out
as a potential source of confusion; I am not arguing that nonchemists
should take on board our definitions.
Peter Breed, M.Chem, D.Phil