LUSHGro contains a general level of NPK and small amounts of other elements. As you are going low tech you shouldn't be dosing so much. You are already dosing N, P and K in powder form and Seachem Flourish contains some (actually quite low) levels of NPK and a good dose of trace.
Let the fish provide the rest. The point of having non-CO2 tanks is to have less dosage, not the other way around.
For a non-CO2 tank like yours, generally the more important aspect is to have a rich base fert and generally let the fishes provide the rest.
I will not recommend ditching it immediately. If I were you I will slowly decrease the dosage over time and see if there are any impacts on the plants. But my guess is that there won't be much.
Here's a good link for Tom Barr's Non-CO2 method:
http://www.aquaticquotient.com/forum...ad.php?t=13623
-Calvin