Originally Posted by
Aerides
Traci, I have the same setup as you. Sun System right? I burn both together. I have the light suspended about 40" above a square growing area of 36". That's my prime real estate. Cattleyas and brassavolas and other higher light orchids are up on pots to get them closer. Higher light paphs are flat on the table. Oncidiums are somewhere in between. Lower light plants (certain paphs, phals, miltoniopsis) are a bit further out and get good light, but from more of an angle. Fan and humidifier (fogger, actually) 24/7. Do you have good heat control? 500 watts does generate a lot.
If you have a lot of higher light plants (cattleyas and up), and you can disperse the heat and keep humidity up, you'll be happier with the results from more light. At least that has been my experience. I started with a 250 watt fixture and quickly replaced it with the 250+250.
All that said, experimenting will tell you what is best for you. Enjoy!
John