Please help diagnose plant problem..

I've started my 29 gallon planted tank a couple months ago. Crypts and
Anubias seems to be doing fine. I have two Aponogeton crispus that is
showing brown spots on the older leaves and finally turning into
holes. New leaves will come out nice and green but will start turning
brown after a week or so. A picture can be found at:
http://www31.brinkster.com/poeshomepage/apons.jpg

Does anyone have an idea what the possible cause/cure for this is?
My tank info:
- 29 Gal
- 1x65 Watt CF with AHS brightkit on 12 hours/day
- Substrate is Fluorite/gravel mix
- Temp: 84 F, pH 7.2, Nitrate 20-25 ppm, Iron ~ 0.1 ppm, no info on
phosphate or other parameters (I don't have other test kits)
- I dose PMDD (only the chelate trace mix) weekly to maintain Fe level
at ~ 0.1 ppm and have been doing ~ 10% water changes every other day
to keep my nitrate down. I'm also struggling with spot algae outbreak
which seemed to pop up whenever I add too much trace elements. I'm not
certain about this tho.
Any help would be greatly appreciated!
thanks so much!
Poe