from the web..
Description- Brown algae, has forked branches may have iridescent blue hue. Here is the thing with the dictyota sp. – there are tons and w/out a microscope the best you can get it down to is like a handful of different species. If it is a brown algae, with forked branches, is not rigid, it is probably dictyota. Some species of Dictyota are desirable, you will be able to recognize them as they grow as one plant that branches out from one distinct holdfast. Removal would be very simple. Nuisance species of Dictyota, (pretty much all the iridescent sp.) stay shorter and creep along the rock. Their branches form straight from the rock, and there is no trunk like feature to the algae, or easily discernible holdfast.
Manual Removal – Difficult. Qting the rock in an extended dark cycle is the best way. It spreads fast, you may want to jump on it. If that isn’t possible, take a dental pick and scrape off every inch of holdfast you can. Get it all the first time and be done with it. At the least get it down to its minimum so the cleaners can polish it off.
Clean Up Crew- Emerald Crabs (best bet here), Sea Hares, some Turbos, Chitons, Limpets, Tangs, Urchins, will pick at it, but it is likely to persist, but at least it will be controlled.
Why it happened – You didn’t quarantine, and you have available nutrients for it.
Starving it out – Use a phosban reactor or a macro like chaeto to take down phosphate. If you have a nitrate problem too, you can add more live rock or rubble to the tank, do some more wcs, add macro, add dsb, etc…
John’s Tip – Under the right lighting it can take on amazing bright blue and green colors. It is a matter of light refraction, more than the health of the species.
