florescents anyone?

I made the switch to MH a couple of years ago and the reef I had suddenly
went downhill. corals and coralline algae all died off. then in October I
started a new smaller reef tank and had some success until I replaced an old
bulb with a new one and now like a few others the algal growth is
unbelievable. I have to clean the gravel at least once a day and the clove
xenia has to be brushed once a day to stop the furry brown algae from
killing it.
now I had a lot of success with tubes before , although five or six tubes in
the one hood is a bitch to fit, and am thinking that my bubble coral is fine
during the early morning cycle until the MH comes on and then it collapses
in on itself then to save it I could switch back.
I had to do a bit of a modification to the MH unit to allow it to run a
double ended tube but this it does but with disastrous results as far as the
corals in my tank.

is this a wise move.

36G main tank with 16G sump skimmed with a prizm deluxe and a RIO1700 return
pump.
Amm= 0
nitrites= 0
nitrates= 5ppm
Ph= 8.7
po4= ?

Robin