Hey Shao
I've run the 400w Radiums on the Son Agro HQI ballasts aswell. The colour is pretty nice... it sure makes some corals stand out. They were a fun lighting system to try out but I prefer a bit more intense/whiter light.
It's really hard to explain the colour of a bulb without actually seeing it on your tank.
There has been discussions about the Radiums loosing lots of intensity while on the HQI ballasts. I think optimum bulb life was estimated at around 6-8 months. I only ran them for about two months but I, without measuring PAR, noticed no intensity loss.
Most 400w 10k tanks, or any spectrum for that matter, look better with some sort of actinic lighting system. Although 400w Ushio are
much whiter than Sun Aquatic bulbs hands down, IMO.
I think any 20k bulb should be run on HQI... they don't look as good on regular ballasts.
Like with any lighting choice it's a toss up untill you actually try it out, or see it in person.
Playing with different lighting combonations gets expensive!!
