Refugium

sorry but im 99% sure thats not chaeto

i agree but it could still be some type of macro algae

Thanks for the comments.

Yes, maybe Japanese Chaeto is a bit different than the one in your country.

It said "Chaetomorpha Sp." when I bought it from online store. Piece like that cost me about $30 since it's very hard to find it here.

How deep is that sand bed?

It's about 4 inches (10cm)

Wanted to add some more sand, but I think it's enough for my setup.