The bio-balls if not rinsed in old SW
every couple of months can collect waste and build up your no3
but it appears it's not an issue so far. It would be better to gradually replace your bio-balls with live rock rubble
which was already recommended.
Return the triggers and damsels to the lfs
or give to a friend if you want a reef tank.
For reef you will need "reef safe" fish, a quality skimmer, and PC
, OR VHO
lighting in the 300+ watt range depending on the kind of corals you want.
Getting your po4
levels closer to 0 ppm
will also need to be done for a successful reef.