Depleted Soil, Green Water

My plant growth has slowed way down since the Aquasoil became exhausted. When I try to compensate by increasing nutrients in the water column, the result is green water with no increase in growth. My thinking is that the slowed growth is inevitable at this point, therefore I should reduce light, CO2, and nutrients to what is required by the present level of growth, and no more. Does this make sense? Thanks.

29 gal w/55 watt Brite Kit/10 hrs/DIY 2 liter CO2. Am dosing for 25 gal using Chuck's Calculator, supplying daily 1/7 the recommended concentration of P,K, and N, as well as 1/2 capful 2Xweek of Flourish for traces and micros. Also dosing Excel according to instructions on the bottle. Change 1/3 H20 every 5-6 days. Plants are Java Fern, Wysteria, Rotala Macandra, and Myiophylam Matogrossense (Parrot's Feather), which is the only one still showing much growth. The tank is probably what would be considered moderately planted.