the mh set without bulb is selling for $75+gst... that is for a 400w, the 250w used to have the same price, but a few days back, they ran out of 250w so due to the demand, they converted the 40w to 250w therefore increasing the price due to labour.. just check w victron how much they r selling now....
$110 is just for the blv bulbs....
victron is located at 705 sims drive #06-07
usual photoperiod i have been recommended is between 10-12hrs... as for the depth, if u would consider 3 inches, above water, not really sure, but i am determining the penetration of light to the base/bottom of ur setup