do not use h2o2, it will kill the beneficial bacteria and microbes in the soil.

my grandma had a good way of putting it, "don't feed the plants dear, feed the soil, and the soil will feed the plants."

also, with good draining soil, oxygenated water is unnecessary, as the soil will breath and the roots will have plenty of air (unless you overwater)

btw, your hps bulb is 4000k? where'd you get that? sure it's not dual spec? 2300-3000k would work better for a higher yeild...

kp