hey alvin..
nice tank.. and nice collection of corals..
btw, i strongly recommend u to add a wavemaker in ur tank.. don juz rely on the return pump.. ya.. it wont provide the sps with enough flow.. somemore, u are driving the pump with ur chiller, FR and main tank if not wrong.. all this sharing have already reduce alot alot of flows.. do consider adding a seio wave maker if u think that tunze provide too much flow, as u mention that only the top u r keeping sps..
anyway, i also starting a 3x2x2 in my dad shop.. hopefully the tank will be nice like urs.. and oh.. maybe u wan to lower down ur MH? i find that it is way too high.. and if u lower down, ur sps will turn out nicer(colour up) ya..
Cheers,
Lorenzo.