Hey All,
Just wanted to share my experiences with ULVA.
I added it to my refugium when my tank was a month old, and it overtook my main tank within a couple of weeks.
It was so successful at absorbing nutrients that my chaeto stopped growing and my soft and LPS corals began to look "sad". They weren't thriving.
I tried a lot to battle the Ulva, including a low NOPOX dosage (1 ml per 25 gal), increased GFO amount, and more water changes. However, ulva seems to take hold and stay there.
The only fish that will touch it is my yellow tang, but it couldn't keep up with the growth.
I also tried a pencil urchin, but it didn't really make a dent.
Finally, I tried a diabella sea hare. WINNER. I still have some ulva, but this cute little guy munches away at it like no ones business. I got him 2 weeks ago, and I expect all my ulva to be gone in another 2 weeks.
For now, I'm slowing decreasing GFO and NOPOX, and trying to get things to be a little more natural while this Ulva outbreak dies down.