Go with Buckeye field Supply on replacing your filters and Membrane. On the 300D you have to ask for them now, they are not a stock item anymore. Being a person who has one if if I was to do all over again I stay with 30" versus the 36". I am 6'4" and I hate the fact I cannot reach stuff in the back. Ace has a 250DD but since he has his as an island he can reach all the way around. Lighting big tanks the edge still goes to MH, but hey if you have the money go for it. I use 3 x 250w MH lumin bright pendants (825 watts total) with Radium lamps that average 16 months before changing.