Java fern black spot

Hi all,
       At the risk of seeming pushy I am reposting my question from a few
nights ago.  I am concerned for my Java fern and hope someone could assist
me.  I hope the original post was just missed.  TIA

        I have been lurking here for around a year, my tank is great IMO,
Thanks everyone!  
        I now have a question that doesn't appear to be well represented in
the archives.  My Java Fern has black spots/blotches and partially
translucent leaves.  A little background, I added the fern, tied to a lava
rock, and in two weeks it was rooted and I removed the rubber band.  Within
another two weeks the fern had grown and started sprouting babies from the
older leaves.  And The rhizome had also continued to produce new leaves and
sent out new sections(split?) and some of the leaves became tribolate.  A
couple weeks after the advantageous babies appeared the older leaves started
getting black spots and then some started turning translucent.  Even parts
of the new leaves and babies have translucent portions.  But on the other
hand, some of the older leaves look great. 
        I have a low light, old, 35gal hex, can only get 30 watts of Triton
in it.  Some of the other plants include: Penny wort, two types of Vals,
Ludwigia, Eloda, Apons, Anubus, pygmy chain swards and reg swards, a dense
grass like plant referred to as micro swards, and a couple of Crypts. The
tank has no real algae problem.   GH 180ppm, pH 7.0, temp 77, Amm 0, Nitrite
0, nitrate <70 ppm, no CO2.  I perform weekly 20+% changes at which time I
add 1/4 oz Aquarium Products Flora Boost, 1/2 tsp Kents Plant food, Genesis
and Jungle Insto chlor chlorine remover.  Fish load: 3 dwarf gouramies, 3
angles, 2 cories, 1 Noemacheilus botia, 1 red fin shark, a ram, and 2
pl*co's(bristle nose and common).  
        The penny wort needs to be trimmed every week and the common vals
are 40-45 in long(were less then 20 when I got them).  I have noticed a
slowing of growth in the past three weeks and have read that Java Ferns can
develop black spots due to a nutrient deficiency, and am wondering if this
may be the cause.  Either Iron, trace elements, or C.  I have also noticed
that my KH and of course pH drops a couple of tenths in about a week, I know
CO2 injection would be a benefit but was also wondering if this is the cause
of my problem. 

Thanks for any advise,