algae
 

My tank is still cycling but this has shown up on a couple of rocks.If it's bryopsis what do I do about it? It's green,feathery and sways easily in the currents.

If you say it's feathery...good chance it is. Are you able to remove the rock and clean it outside the tank?

Crappy pic I know but def feathery.I can remove the affected rocks if need be.

At the start I had a small rock with that...I took it out and gave it the acid treatment. Now the rock is nice and happy and back in the tank.

Hair algae! Cut your lights, they dont need to be on during the cycle. This is normal, don't stress too much about it.

Acid? No lights? Would vinegar and a toothbrush work? If I turned out the lights how would I stare at the big box o water? I tried to pull some off with my fingers but ended up losing some in the tank.Oops.

What are your params at? You could add your cuc if it's done cycling!

Just cut the lights for a few days. I threw a couple of rocks in my 180 that were covered and my tangs devoured it!!

Using acid is a final approach to remove this unwanted algae 100%. I used muriatic acid and it works like a charm. If you were to go this route i'll give you needed info on how to do this safely.

Vinegar won't do a thing...just kinda whacking an elephant in the ass...it won't move.

The fact that your tank is still cycling means you shouldn't do anything other than maybe cut your lights. Algae is a normal part of the process. Sterilizing your rock with acid will just take you right back to where you started, and should be used as a last resort for truly insidious species of algae that show up in stable systems and can't be removed any other way. You'll see many different kinds of algae pop up, spread, then recede as your tank matures.

Edit: I just looked at the pic, it looks like you have a mix of true live-rock mixed with marco rock, and that the algae is on the live-rock. This is completely normal, and the algae will very likely spread to the marco rock soon. Again, completely normal process of the tank cycling and becoming populated with an ecology. Dipping your live-rock in acid - which I assume you bought specifically to seed your marco rock - would be extremely counter-productive at this stage.

Thats funny! Ok no vinegar.My params are ng at the moment.As of this morning in the cycle my amonia is zero but nitrites are off the scale...I think I will try scrubbing it off and give that rock a stern warning...and ride it out.