That's great you've gotten to the point of pruning back caulerpa. You're right about it outcompeting other plants with its fast growth.
I've had a love-hate relationship with mine. I love the look of it, I love how much export I get when pruning it back. I hate that it sucks up everything I dose the water column, outcompeting my seagrass. That's why I turned to substrate fertilization. If I had to do it over again, I'd plant my tank with lots of manatee grass only. Then, after it was very well established, I'd add macros. But that's only because manatee grass is my pivotal species (priority). When keeping macros and seagrass with equal priority, I think you just have to accept the disparity in growth rates and adapt and work with it.
Michael,
Your biotheme tank looks great. When I heard pivotal species, I thought of
John Tullock's book "The Natural Reef Aquarium". The book coalesced my reef keeping husbandry. My favorite quote from his book is "Less technology/More biology".
From your experiences with sea grasses, once established, do you feel that maintenance upkeep with sea grasses is easier than macro algae?