Bug in my tank?

[Dragon780]

hi guys, today i saw a bug like critter in my tank and crawled into my live rock, its the size of a ant, and has alot of legs lol more then 10 for sure, its white i believe, i dont know what it is. can anyone tell me? and also my still cycling, so i have nothing in there besides rocks, some rocks i bought from someone, and some are new rocks from local supplier.

my second question is, my tanks been cycling for about weeks, but the waters still so clear, is that normal? and when do i know my water or rocks are ready for fish?

thank you everyone