Goniopora - Not happy - Algae issue??

[Rachelh01]

I've had this Goniopra for a week, and it has been great as you can see from the pic dated 08.07.20 it has been opening up for the last 7 days. Today however it has been closed up all day as per the pic dated 15.07.20 and looking really closely I'm not sure if I can see (or I'm imagining) what looks like brown algae on some areas?

Tank is Red Sea Max Nano with sump, been running for 6 months, 2 x clown fish, 1 x orange spotted goby plus CUC, 1 x Hammer coral, 1 x Zoa, and addded at the same time as the Goni was 2 x small pulsing Zenia heads (not fully extended the last few days either)

parameters tested today with salfert test kits:
Temp - 25.3
ph - 8.15
Ammonia 0.15 (always been this)
Nitrite - 0
Nitrate - 25 (again always been this)
Salinity - 1.026
Alk - 7
Calc - 440
Mag - 1380
I dosed 4ml of reef fusion 2 to raise Alk and added 100g of Rowa to reduce phosphate (removed old bag that i think has stopped working hence the rise)

Any clue if that is algae and if so what can i do for it, or why it hasn't opened at all today??

 

[shwareefer]

I see flatworms. Brown spots on bottom. Do they move?

 

[Rachelh01]

no brown spots not moved at all, a couple of the polips slightly extended yesterday (but not by much) all the rest still looking the same :-(

 

[Rachelh01]

I see flatworms. Brown spots on bottom. Do they move?

I got up today and they have moved!
managed to suck one up with my coral feeding baster and isolate in a container and i can see it moving! you were correct they are flat worms - thank you!

next question - how do i treat them and do i need to isolate that coral in a quarantine tank (currently don't have one) or can i and would i be better treating the whole tank??

 

[shwareefer]

I haven't had to do a dip in a long time but I used to do a container big enough for the coral of RO water with a few drops of iodine and a few drops of salifert flatworm exit. Submerge the coral and shake it all around for 30 seconds or so, max 2 minutes. The kewl kids these days are likely using CoralRX or something similar but the process is the same. Perhaps someone still freshly adding corals will chime in.

As for treating the whole tank, flatworms release toxins when they die, so if you happen to have a lot of them in your tank, it can be detrimental.