Uncle Salty, I have been running the 250W 20K bulbs since march. No I'll affects so far. I didn't have a lot of super needy light stuff at the time so I thought what the heck can't go wrong. I bought mine off eBay for 20 bucks apiece. I've had great luck with them, I keep an LTA, and a RBTA, zoos, ricordea's, candy cane, clam, and a few other corals under them now, all showing good color and growth. Haven't had any algae issues show up either. I typically run a 14 or 15 k bulb, but a lot of the reviews I read said that they aren't as blue has a name brand bulb so I went with the 20 k and love the color.