On a side note, I stopped by Vivid Aquariums about a month ago and they are doing the same type of experiment/comparison between Metal Halides vs LED's on their main display tank. I was really amazed at the difference in the overall appearance between the two. If it was not for the heat and...
I would have to disagree about the HLLE association with running carbon in the article. With the amount of aquarist that run carbon, I think we would notice a higher incident of HLLE. However as some have mentioned on this thread if your tank runs fine without it...great!
When I used it in the past, 3 weeks was the sweet spot for me, but from the replies above it looks as though its all a matter of conditions tank size, feeding, etc...
I thought your biopellets were helping with the PO4 issue????
Just realized that my QT tank has no temperature controller. I'm more worried about excessive heat. Are there any alternatives with a lower price point than having to purchase a controller i.e. RKL, apex jr, etc... that would kick on my fan when the tank reaches a certain temp?