What are you talking about, little pc's that sit in nirmal irridescent fixtures and use 20W and it says 100 watts irridescent output on the box?
Well they're good for small tanks, but while it might be the equivalent of 100 watts of irridescent output, it's still only equivalent to 20 watts of fluorescent output, but more concentrated. Plus usually in a low K range. So good for small tanks, refugia, but for big displays, don't kid yourself - if they worked every one would use them