Went away for a week. Think the house sitters fed tank too much. Fish all fine (2 Ocellaris, 2 Banggais, and a Royal Gramma). Ammonia 0, phosphate nearer 0 than the first colour on API test, and Nitrates indistinguishable from the 0 colour. But tank covered in hair algae, and other algaes on sand and glass (orange spots?). Got a brown emerald crab (cousin to emerald?), but no snails at lfs. Going to bigger store Tuesday so hoping to grab a tailspot blenny (very unlikely), a few Astraea, a few zombie snails, and a few Trochus. Hopefully help. And yes, I scraped everything I could and did a 20% water change first thing. Kinda amused by the hermit crab with the Trump hair though.