What do you mean when you say that your plants aren't doing well? Algae? Damaged leaves? Little or no growth? At any rate, if you're switching to a low light set-up, then you don't need the pressurized CO2. As for EI dosing, you could still keep doing it, but you'd have to modify the dosage. For instance, my low light nano tank gets 25% of the recommended EI dosage and is doing great. I'm sure your anubias and java fern would appreciate a least a bit of ferts although I think you could probably do away with dosing the water column completely if you wanted.