What Are These Things

[Matt]

Originally Posted by Myka

The last brown one is Padina...get rid of it. It will spread like a plague. Be sure you don't let any little broken bits of it float around either as every little broken bit will grow a new one wherever it lands.

I am shocked to hear padina maligned so... it cycled out of my tank when the nutrient load dropped. It was quite pretty, and I do miss it. Reefkeeping mag counts it as desireable, too. Anything can be a weed, if it grows where you don't want it, I guess.