A 70 watt
HQI will be enough to support SPS. The basic rule with
MH/HQI is that each bulb will cover approximately (depending upon height), a 2*2 square. The depth of the light is what changes with upping the wattage. So a 70 watter may not do well at deeper than 12", while a 150 goes to about 18-20", and a 250 watt
HQI goes to 24-36"...and these are all depending upon variables in light, spectrum, etc.
Does that help?
-Jon
