My lotus stays small for ages (also no ferts) then suddenly takes off shooting huge leaves to the surface. It then flowers and dies back again to repeat the process. You can cut off the longer stems. Lighting has an effect on their growth, or size, too.
I am not keen on the filter/heater combo mainly because if one dies you have to get a replacement, either another combo (and double up on the bit that didn't die) or another piece of equipment in the tank. I prefer to be able to replace each separately.