if by the big blades you mean sword plants then i was told its normal because most sword plants are grown in an immersed form,(they grow faster like that) and then when you completely submerge them there leaves die off and they grow new more slender ones.
i have a 100 gallon tank with a fluval 404 canister filter, a surface skimmer powered by an aquaclear mini power filter with the sponge and carbon package, an AC802 powerhead with the filtration attatchment filled with those ammonia killing rocks, 5 piranha's, 1 sailfin pleco, 2 fake plants and a few live plants, water parameters are all normal nitrite-0ppm, ammonia-0ppm, Ph-7.2, and nitrate os about 20 ppm. i dont know hardness, im gettin a hardness tester tomorrow.
i am using 2 repti-glo 5.0 uv bulbs, i have normal black gravel from big al's, and i used some of that iron enriched plant gro stuff, and what do u mean by fertilizer? i was told to use that peat fibre stuff in my fluval canister filter. is their something i should be using?
Remove the dying leaves to promote healthier ones to grow. Im assuming the bulbs are about 50 watts. This is a pretty low wattage for a planted tank. The peat in the filter will soften your watter and lower the pH slightly. If this creates a favorable conditions for your species of plants it could help. Here is a great article on keeping your plants healthy and happy.