How long has the tank been set up?
What are the water parameters (ammonia, nitrite, nitrate, pH, alk
How much flow do you have in the tank?
What kind of hermits and how many do you have?
Have you done a search on this site using "cleanup crew" as a keyword?
I'm not trying to get out of answering your question, but you may find some good info that way. You might be able to get the LFS
to order your crew once you decide what you want. Shipping is pretty high on live critters and it may not pay you to order online for a small order. Your algae (guessing) sounds like diatoms. Can you post a pic?