A. Congensis & Swords - strange growth

Tank 4 feet long, approx 32 Gallons ( 39 US Gallons ). 2 * 40 W Tritons.
pH 6.9, Temp 25 'C, Nitrate 5 ppm. 25 % weekly water change. RUGF. No 
regular fertilization program, just the odd squirt of cheap aquarium fertilizer
from time to time. No CO2, plain gravel. The tank is in a steady state and has
been for over 18 months or so. Densely planted, medium fish load.

These observations are probably unrelated but as I don't post very often I
thought I'd just lump them together! 

1. Amazon Swords. These plants were surviving but growing weekly for about 2
years until about 6 months ago when they started accelerating. The leaves are
about normal size (?) approx 5 by 3 inches but the stems have started growing
very long > 20 inches. So now all the leaves are out of the water and the
stalks push the condensation cover and light fittings off the top of the tank.
From the normal viewing position of the tank all that can be seen is the thick
green stalks.

2. Anubias Congensis. I planted 4 one inch long rhyzome pieces of this plant
12 months ago; 3 in well lit areas and 1 under the above-mentioned monster 
swords. The first 3 are thriving and have grown well but the one under the 
swords is miserable. I decided to move it and when I dug it up I was amazed by
its roots. The rhyzome is still about 1 inch, it has 3 tiny leaves only, the
biggest of which is 2 inches but the roots were 14 inches long! I've never
seen such disproportionately long roots, and I,m sure the plant's trying to 
tell me something.

Ideas anyone?