What size tank, and what is in it? The hillstream loaches come from cool, fast flowing streams, and tend to suffer in warm, tropical tanks--both from the higher temp and lower oxygen levels that come with warmer water. I don't think they have a reputation for eating algae, either.
If this is a new tank, manual cleaning is probably best for now. If the diatom algae continues to be a problem after the tank has been established for few months, then a trio of otos would help clean it up.