I suggest you wait for the tds meter before you spend any more money. RO is the shit, but you don't need it to have a nice grow. Those aggressive feeding schedules are for mature plants that can handle it. I would consider your plants to be mid-sized. I would be feeding 700-800 ppm with RO. If your tap turns out to be 700+ ppm like THC has, you'lll want to get that RO unit. My tap is 200 ppm and I had to buy an RO unit just for my humidifiers.
I've just recently started seeing HPS -> MH conversion bulbs for 600's.lumatec 600 hps,thats my two cents,600s give the highest lum-watt ratio, you can't get a 600 mh bulb though, nobody makes one,yet.
Get a 6in air cooled,Xtrasun 6in under 100 for the hood and socket
Right on, User, you always find the good stuff, owe you again.I've just recently started seeing HPS -> MH conversion bulbs for 600's.
HiLUX GRO MH Conversion Lamp, 600W - Worm's Way