I have 2x175W MH bulbs + 2x55w actenic PCs on my 72G. I used to have a no name 13K bulb (Catalina I think) that came with the retro kit. It was actually more yellow than white. It looked more like 6,500K really. One of the bulbs burnt out and I ended up getting 2 new 15K coralvues. I like the color much better than before. I put them in last night and today most of the corals (especially the ones place higher near the lights) are closed up. The zoos and frogspawn which are on the bottom don't seem botherd though. Is this normal after changing the color spectrum. Both old and new bulbs are 175W, the only different is the color??? and if so how long does in normally last?