potassium suplimentation

["Eric Wahlig" <ewahlig at earthlink_net>]

Awhile back there was some discussion about which salt of potassium to add
to a planted tank as a means of boosting/replenishing K. Much of the
discussion centered around the possible effects of these on Cardina
japonica shrimp. Potassium chloride(KCL) was thought to possibly have
detrimental effects by contributing too much chloride to the water.
Potassium sulfate(K2SO4)was thought to be a safer choice as a higher level
of sulfate in the water was considered less of a problem [osmotic stress?].
I found this site regarding the shrimp:
<http://users.skynet.be/caridina-japonica/> and see the breeding section.
So, I don't think the higher chloride concentration from supplementing with
KCL would be a problem. Therefore, I'm wondering if it would be better to
supplement K with KCL rather than K2SO4 as I already add SO4 through Epsom
salt (magnesium shortage in tap water).

In looking at the Optimum Aquarium book, it lists the mineral content of a
certain Cryptocoryne stream in S.Thailand [page 68]. Of the anions and
cations in solution, this water is about 50% chloride and sodium
respectively. This further suggests that an elevated chloride level is not
detrimental.

My tap water is devoid of nutrients. The municipal water supplier adds
calcium hydroxide and CO2 to bring the pH up. The hardness is about three
degrees (50mg/l). I add some more CaCO3 and MgSO4 to bring the calcium up a
little higher and provide magnesium. The question is on providing K. K2SO4,
which is what most people are using ?, will provide a water with lots of
sulfate and no chloride. Adding KCL will provide a water with sulfate and
chloride. This may be better balanced water in my case. I am not a grad
student in chemistry or anything so, any comments or remarks would be
appreciated.   

--- Eric