New tank live rock going grey
 

I started a new tank about a month ago. Every is doing pretty well water is tested and looks good. Started with 10yr old live rock some zenia, mushrooms and sponge , which is the affected section. Which is fairly small (1x2 inch) can any one tell me what they think this is. The section also has a colony of small white worms that curlled up and dont really move.

Hi, welcome to the board.

First, 10 yo rock is potentially full of nutrients. When you say water is tested, please list parameters, it helps a lot. NO3, PO4, NH3, salinity, temp.
Also, give details on flow and lighting.

It sounds like you might need a bit more flow over that area, maybe get some oxygenated water flowing over it. It could also be a dying piece of sponge, they often go gray.
Without a pic, we're just guessing.

Welcome to Canreef :welcome:

if the rock was out of the water for any amount of time some of the sponges prob. died. Is it fluffy gray or hard.

ya i think its the sponge dieing off. It is the bottom part of my bridge that doesn't get much light. As far as testing, calcium is 400ppm nitrate and phosphorus is near zero and alkalnity is 8 dkh and lighting is 24" coralife 65w 50/50 PC with 24" T12 20w 6000k

i read it was a good idea to brush dead spots off live rock. is this true, would it be better to just leave it alone

Just a word of caution... That T12 6000K bulb is probably going to grow algae like nobodies business.