yeah, i like my radiums. not crazy about the price tag though.
yeah, running it on an HQI ballast, which if i remember correctly...is around 330w.
the last one i changed out had 6months on it. is there a noticable difference b/w a brand new bulb vs. a 6month bulb? yes.
with the older bulb, after running it about 6hrs the bulb becomes more and more white. maybe slightly dimmer.
did i notice a change in growth b/w the older/newer bulb? probably a little bit. but i'm more about things looking good than corals growing like weeds. if corals grow too fast that just means more time i have to spend cutting them or upgrading. so i just assume they grow slow and look good.
the only downside to the radiums that i can see is pinks dont pop as much on some corals. but it may be that the corals just have to get used to the bulb. my pink milli with blue tips looks hot right now. but the pink had faded around the 4month mark on the older bulb. took several weeks to get back on the newer bulb. thats the only real color difference i've seen in any corals.
but then again, i cant blame that all on the light since my calcium/alk ratio was jumping around for a bit while i got my litermeter zero'd in on the right settings after about 2 months.