Just jotting a thought down.
This tank was running great with carpeting, minimal algae etc.
Then I did a major trim (shown up above) and in the process think I discovered the devil that is the inverse square law of lighting. The plants took a couple of weeks to recover from the trim, and when they took off, started slowly and then accelerated very quickly as they approached the lighting. The period of slow growth allowed a solid amount of BBA to gain a pretty good foothold in my tank.
This is why you may have noticed that despite my frequent praise of the Coralife fixtures for their low light low algae, I am now starting to look at lighting that I can suspend higher above the tank (and maintain low-medium lighting at substrate level). That should allow me to recover from trims quicker and maintain more consistent growth.