Ivo, You have rated the AX-50 above the Triton tube for PAR. Is that the Philips f40/t-10 50AX? If not, what bulb is it? And if it is, what about the ultralume bulbs by Philips? I know they are not as bright, but I was thinking of running a 50AX and a 75UL for a mix that would end up around 6000K. Objections or general comments on this are welcome. Bob Dixon