Pag bago pa lang ang tank mo, expect algae, unless you have a super efficient skimmer. Get some cleanup crew first. First stage of your cycling are diatom outbreaks, tapos yang hair algae and if kulang circulation mo, cyanobacteria will follow. It's a natural process.
After your tank has cycled and tests zero amonia and zero nitirites, make a 25% water change and check your nitrates, it should be below 10ppm, then get a tang to eat the algae. I was surprised that my Paracanthus hepatus (dory) ate all of my hair algae. I also recommend urchins, though they eat coralline alagae as well.
I know this is a sand topic...So OT po.