ID Please nasty lil things...

[SC350Z]

I had an outbreak of these white things a while back and long story short then tank started going south and we were getting ready to move so it just kinda got let go... Are these things safe or not? They wouldn't go away... They were all over the glass and everything...
Another question my tank got bad during the move and it had a bunch of slime create on the borders and fell down to the sand I just did a major clean like got all the water out and as much slime and contaminants as possible so now I just have sand in the bottom I put the rocks and coral in a separate container in water...
Is it ok to just mix up some new salt water and start the tank over or does it need to be cleaned ? Like I don't want to mix all that water up again and do all the work if the algae is going to restart nasty... I think the algae started bc during the move I never turned the filter on so there was no water flow.

 

[MINItron]

Those are just tube worms. They are just part of the ecosystem, and certainly aren't harmful in any way.

It sounds like at this point you essentially starting back over as a new tank. Your tank crashed during the move, and recovering it now is going to be difficult. If you scrub everything down, and start with 100% new water it will be the same as starting up a brand new tank.

 

[SC350Z]

I scrubbed the walls down and got all the contaminated water out and I've been putting new saltwater in... and got a bottle of Seachem Stability... Dude at the LFS was very helpful and I'm going to do a full treatment of this stuff today and half dose treatments the rest of the week to get the good bacteria flowing and then take in a sample this weekend and we'll go from there! I'm ready to get this thing really going this time!
Thanks for the advice and info on the tube worms man!