they are ok. I had them in my Nuvo and took them out. Vinegar bath and they are back to new. if you put them in when you start cycling or right after you will get the coverage with coraline the same as with live rock. but if you put them in after you will have a bright white rock until it gets covered.
IDK.. $40 bucks for all three sound good?
retail is $25 x 1 and $15 x 2 plus shipping.