Plants are constantly dying but growing new leaves.Older leaves turning yellow and becoming transparent.?

My plants are amazon swordplants,Java fern and Java moss.But only the Amazon swordplants are dying. Sometimes I think I over pruned my plants.How do I actually prune the plants and keep them nice and tidy?I always seem to do a pretty bad job and the plants looks horrible after awhile.I have a CO2 diffuser,fertilizers with occasional dosing of liquid fertilizers and trace elements.Using 2 fluoroscent lamps with reflectors.The 2 tubes has been used for quite some time.There's always little particles floating in the water,i think my filter isn't up to the task anymore as I have what I believe a pretty heavily stock of fish in a 4ft tank. 2 adult and 2 baby angelfish,2 striped raphael catfish,4 bronze cory,4 panda cory,4 oto,2 wood shrimp,a few yamato,20 rummy nose and 20 cardinal tetras. Will be getting another filter,so that I have 2 running simultaneously.Temperature used to be quite high,until I removed the lid.