Thanks Mad Scientist, for such detailed information. I think the algae is diatom. My tank has been 2 months, live rock, sand cycled using sea water. Corals branch hammer and gsp came in about 6 weeks ago. Cynarina abt 5weeks with 2 false clowns n 1 cleaner shrimp. Added 1 yellow goby abt 3weeks ago. Added mixed frags of mushroom, clove polyps n zoas, 1 bubble and 1 sun coral. Realised that was when the algae really increased with alternate days feedings. Not sure about water parameters but ammonia indicator shows ok range. Filter is stock filter with stock led light. Using IQ5 skimmer. No chiller. With exception of sun n zoas, the rest seems ok. Gsp is weird though, sometimes the top part opens and sometimes the bottom polyps open. Actually quite happy with tank but really think cannot keep the Sun coral happy.
As for the rest of your terminology like skimates etc, I'm afraid i'm not so sure what they are. But I appreciate all your expert advice. It's great learning for me.
Read that for pico like mine, no need to measure so many parameters and add many chemicals cause it's so easy to overdose, so juat change water at least once weekly. Is this true?