Hi, my live rock has patches of hydroids on it. LFS is soaking the affected rocks in RO water. Also adding something that will kiill it...along with other beneficial bacteria. Rats. Also see white feathery , very small, "things' on other rocks. Wetwebmedia states that these will go away on their own, yet another form of hydroids.....Any of you experts have any experience with these. I am bummed, have done water changes, Water has been great....just put our two first fish in yesterday, 2 perculas. I am not treating all of the rocks at once because I do not want to totally disrupt the biological filter benefits. Will put treated rock back in, then wait for it to re-cycle. Any advice, please, we are bummed....have been soooo careful.