Thanks! they call it red grape algae at the store...i got it for free when i got my seahorses. It started to die off with my old light so i started to shine a lamp on it and that is the new growth.
i copy and pasted this from another website
"Red Macroalgae (Botryocladia Sp.)
Sometimes called "red grape caulerpa" although it's not caulerpa at all.
Long slender branches that extend to rows of bright red bladders.
This is considered a rare variety. Commonly found on reef ledges.
Requirements: strong light, iron & manganese.
This algae works great for both nutrient export as well as feeding something nutritious to your algae eating fish. If you intend on growing this to use as a consistent source of nutrient removal or fish food, you'll have to grow it in a isolated place in your system as algae eating fish will devour this algae in no time.
I'm told it grows slow due to only having one root system (unlike green grape).
also told tangs like it more than green grape in general. "
I believe it should look like this and hopefully not take over my tank
Google Image Result for http://image30.webshots.com/31/0/74/30/225507430pqckWH_ph.jpg
(this is just a googled image)