Here is a post I put up awhile back, I hope it helps.
I had bubble algae in my 180-gallon reef tank bad, real bad! More than half of my rock surface was covered with a solid blanket of deep green bubble algae. It was getting very discouraging and I wanted it gone. One mistake I made was letting it take a hold and get out of control. However, I was able to get rid of it practically overnight and it has not come back for months. Except in my overflows. I obviously can't guarantee what worked for me would work for anybody else, but here is what I did.
1. Purchased 50 mexican red-leg hermit crabs from bluezooaquatics.com I got this idea from a credible source which also had a bad bubble algae problem and also beat it. Suposedly these particular hermits from Bluezoo eat bubble algae.
2. Purchased 6-emerald crabs from various places
3. I scraped the bubble algae off the rocks with a metal spoon. I'd say that about 50% of the rocks I scraped underwater and the other 50% I was able to take out of the tank and scrape the bubbles off in the backyard, then I would pour a little tank water over the rock before putting it back in the tank. While doing this the bubbles were exploding everywhere, shooting liquid all over me including in my eyes and in my mouth.
4. I tried to scoop off the rock as much as I could with the spoon in the backyard, however, there was a ton of rock which I was not able to get out. I scraped all the bubble algae off these rocks while they were still in my tank. My sandbed had bubble algae all over. (all pumps off during this process) Then I took a net and caught as much bubble algae as I could which was floating in the water column.
5. I purchased a Scribbled Rabbitfish (S. Doliatus). It did not take long before the Rabbitfish was eating the left over bubble algae, right out of the water column. He was going after it like a tang goes after food. Then after he ate it all he started picking remnants of bubble algae off the rock too.
I am very relieved to be practically bubble algae free now and was shocked to see how fast I was able to get rid of it. I knew I was at risk scraping the bubble algae off underwater due to the chance of spreading it, but it was a risk I was willing to take. I believe that if I was to get rid of my hermet crabs, emerald crabs and rabbitfish that the bubble algae would probably come back. I think they eat the spores once they settle, not allowing them to become a nuisance again.
I heard from some people that I was doomed because the bubble algae could still grow in a low nutrient system like mine (and it was continuing to grow) so it is much harder to get rid of than just adding GFO and keeping low Nitrates. One lfs told me I had to throw my live rock away and another said valonia/bubble algae is worse than hair algae.