I had an ATS on my 40 breeder, I used it for 2 months and got rid of it. Pulled my nutrients to 0 (nitrate,phos) and my acros looked like crap. I turned it off and just feed a bit less keeping my nutrients lower and colours came back.
On a local facebook group ATS's are all the rage and a ton of new comers to the hobby think they need them without really understanding what their problem is or why they want it. They have their places, no different than growing chaeto. But i tend not to add more equipment that can fail for a problem im not sure i have. Just my 2 cents.