Symptoms - Cryptocoryne beckettii

I have a Cryptocoryne beckettii in a 29g planted discus tank that is the center piece of the tanks and really something to see ! It has thrived and grown very large and beautiful over the last 6-9 months. Lately I have noticed some light gray streaks appearing on more and more leaves and some indication of progressive decay on some of the smaller/newer leaves. Most of the older leaves are large dark-green/red and show no signs of distress. I am trying to figure out what may be causing this ??

Up until a couple of weeks ago I had 3-20w lights and have added a fourth 20w florescent totaling 80w. The original tubes consisted of 2 Coralife Trichromatic and one Coralife 50/50. The fourth tube added is a Coralife 10,000K. I use DIY mylar reflectors in both of the double-tube fixtures.

Co2 - Consistent 20-30ppm by Lamontt test kit. Injected (as of Christmas present from wife, did not expect this one .... what a shock !) 1 bubble/second into Advanced Reef Tech reactor (not thrilled with this reactor design because I think it lets too much Co2 escape).

Nitrates/Phosphates: Nitrates are sometimes consistently a little high in the 10-20 range, never over 25ppm.

I use Seachem's phosphate and Puragen resins in the magnum for excess Phosphate/Nitrates. With planted discuss tank and with feeding beefheart I think this helps control P/NO3. I also vacuum some of the top layers of substrate with water change.

Hum...haven't measured phosphates in a while. Hold on a second....... P = 2.5-3.0mg/l (SeaChem) NO3 25mg/l(Tetra Kit). YIKES these are high ! I am using the low-range Seachem P kit. In the directions it says: "Usually, freshwater phosphate concentrations will be beyond the range of this kit (0.0 to 3.0), and dilutions of sample with distilled water will be required. If excessive algae growth is not a problem ( and it is not, NO hair algae in the tank), then the phosphate concentrations may be considered as acceptable". Well ok. Does this sound ok the ADPers in the know ?? Just did a water 30% water change and will test again tonight diluting the test sample.

Substrate: Bottom Pond Planting Soil (this is just very fine fired-clay granules w/ supposedly good CEC, no organic matter in it), DuplaK lateraite balls pushed in deeply. I may lack Ca/Mg in the substrate after thinking about it ??

Water Column: DuplaPlant tabs (the smaller ones for 20l), drooped in Magnum 350 with weekly 30% water and filter media/floss cleaning, 2-3 DuplaPlant24 drops/day. No UG heating at this time. Maybe on the new 90g...I wish !

Bi-weekly add 1-3 tsp... Kent's Fresh Water Plant Food if I think the plants are showing signs of iron deficiency or if my useless RedSea Fe kit looks on the low side. It measures .1 usually, (It looks like I need to invest in the Lamott or Hatch Fe kit after all).

I Feed sparingly 2 3-4' Discuss ( 1 high-fin turquoise and one red) I soak Jack Waltney's and M3's DISKUSIN with Kent's Zoe vitamins over night. Also feed tetra flakes, Spirila (sp?) and tetra discus-bits.

Other plants look good and growing well except for two Amazon swords that seem to have stopped growing all of the sudden and are developing green algae on the leaves. Java Fern (getting more algae) , Hygrophila polysperma, Sunset Hygrophila, Anubias barteri v. nana, Lilaeopsis brasiliensis, Aponogeton rigidifolius, and Bacopa caroliniana all seem to really be perking up with the addition of Co2 (Duh!).