Double Amen Brother. I have the exact same issue.
I mean seriously fellas, I read tons of threads on chaeto-- and you get so many answering how to get it to grow with spending more money on special lighting- when you know the light you are using is proven to grow it, or they suggest getting it to grow by adding more supplements etc.. and then you tell all the stories of how you now have chaeto coming out the kazoo.. But all that stuff gets everything else growing as well it seems..and the chaeto may still not grow-- making a bad situation worse-- so in essence the underlying question is never really answered: At what point is your water chemistry such that chaeto is not worth having and better to work on the pods, algae issues some other way?? (n.b.. as a side note I read you could use rock in your fuge to house the pods instead of chaeto)
Now if some of you had zero nitrates and zero phosphates before you added chaeto, and are doing well with it, even just sustaining it with modest growth, then there is mystery there that is not yet solved. I do not buy the lighting thing, but perhaps somewhere you have something in your chemistry that is making it work.
I grow chaeto so my pod population has a place to live. I also have live rock in my sump.
I have zero algae in my display tank except for some film algae on the glass that I clean every 3 or 4 days. It gets just thick enough to bother me when I am looking at the tank in 3 or 4 days.
I do not know if the chaeto is keeping the algae out of my DT or not, but I like not having it in there.