A few weeks ago after changing my yeast CO2 system to a new, far more
productive batch, I started to notice problems with my crypts. Around the same
time, I also changed my dosing regimen (Flourish and Flourish Iron) to include
Flourish Potasium. The crypts also have Florish plant tabs near their root
balls. After this, I noticed the crypts started having leaves disintegrate. It
started with a small lession that bubbles oxygen (I assume) as shown in the
following (somewhat poor quality) photograph:

http://www.shwaine.com/image/fishtank/crypt_leaf.jpg

Then the whole leaf disintegrates outward from that. Also, new java fern leaves
have a distorted appearance, almost like certain portions of it are being
pinched inwards, creating a jagged edge instead of the normal leaf appearance.

I've looked at the following nutrient deficiency chart, but there really
doesn't seem to be a description that adequately covers all the symptoms:
http://www.thekrib.com/Plants/Fertil...eficiency.html
Potassium sounds kinda close for the crypt, but doesn't seem logical since I
was just starting to add more potasium.

The stats of the tank are available at http://www.shwaine.com/fish_40g.html