We do recommend as many different species as you can for the reason that each species has their own preference to ideal conditions to grow. I know in the US some states have limitations as to what species you are allowed, especially caulerpa, so you can only use what you can.
If cheato is what your system wants to grow then let it, even if it does dominate over other species, there may come a time where your system goes through a bit of a shift in parameters and a different species now takes the batton and becomes the dominant species, this happens a couple of times a year in my personal tank which I put down to seasonal changes externally having an effect. It only takes that one leaf hiding in the corner remaining patiently waiting it's turn....
The above is also why we recommend a full spectrum algae light as although a LED security light may be excellent at growing Chaeto the moment one of the other species might want to have a go at taking the lead if the light is not up to it then the algae bed will suffer...
If cheato is what your system wants to grow then let it, even if it does dominate over other species, there may come a time where your system goes through a bit of a shift in parameters and a different species now takes the batton and becomes the dominant species, this happens a couple of times a year in my personal tank which I put down to seasonal changes externally having an effect. It only takes that one leaf hiding in the corner remaining patiently waiting it's turn....
The above is also why we recommend a full spectrum algae light as although a LED security light may be excellent at growing Chaeto the moment one of the other species might want to have a go at taking the lead if the light is not up to it then the algae bed will suffer...