I purchased the Iwasaki 175w 15k bulbs and they were delivered on Friday. It's only been two days, but I immediately noticed how much more brighter (and whiter) the tank looked than it did while using the AB bulbs. The colors of the corals are better too. I also have uri super actinic vho's. The actinics only provide the best coral colors. Actinics along with the the AB bulbs give me the same colors as the iwasaki only bulbs so I don't need to run the actinics and the Iwasaki's to get the colors that I had with the AB. The actinics with the Iwasaki provide better colors than the others except the actinics only. The only problem with the actinics only is the tank is too blue. I like the Iwasaki bulbs.