Question: Holes and Potassium?

Hi All, Neil Frank, David W., Karen Randall, and George Booth all come to
the conclusion that my new, emerging Echinodorus leaves get holes in them
when I remove the older, outer leaves because I am taking away a nutrient...
potassium.  What aquarium brand fertilizer can I use to supply more
potassium?  I can't think of a product for sale with potassium listed on the
label.  If there is one please let me know what it is so I can buy it.
Could I put a banana in the substrate?  ;)  Should this be supplied in
liquid form or be put in the substrate around my Echinodorus?  I am under
the assumption that Echinordorus are root feeders and won't take much in the
way of nutrients through the leaves?  I am under the assumption that
stem/bunch plants take most of their nutrients through the leaves and less
through the roots?  BTW, I got my water report and it checks out with my
test kit readings of 1dh of KH and 6dh of GH.  The alkalinity also checked
out the same 10 mg/l.  The test kits were right in step with the water
company.  I was surprised to see this.  I add nothing that I know of in the
way of acids.  I use API Stress Coat and API Tap Water Conditioner to
dechlorinate the water.  The low alkalinity must be the reason  my pH falls
to 6.0.  I think I will try the baking soda that was suggested to bring the
KH and pH up, and then go with CO2.  I want to thank all of you for your
help.  I need it.  <G>


"There are always exceptions to the rules"