sea urchins

[mfrei64]

I have two hungry urchins that never stop. I know they eat green, red, and brown algae, but do they also eat purple coraline? I seem to have less than before, and white patches where it used to be.......

[Atari]

Welcome to the forum

Yep, urchins eat coralline too. It's either that or your coralline bleached from too much light.

[mfrei64]

I've heard from some that metal halides reduce the purple coraline, from others that it doesn't? True?? I'm running 4 metal halides, but in certain spots the purple is great, and in others it looks like white patches....more like somethings been eating them.

[quarryshark]

Try target feeding them some nori. Mine eat it with gusto.
May slow it down.

[Nitrate]

I bought a pincushion a couple of days ago and it has almost stripped a medium sized tonga branch rock. The pincusion seems to be more thorough than my long spined are.

BTW welcome to AA