Antipofish, I appreciate where your coming from but I am merely stating my own experiences from a long time in dealing with equipment and the hobby. Yes it's a guide line, it's flexible but it's a very useful one, I know why the rule exists and it's ins and outs. I also think you're taking my point on surface agitation to a relative extreme, surface agitation is a good thing especially during the photoperiod. A nice ripple is preferable, it allows better gas exchange, more o2 in the water and healthier fish, yes some people have floaters but then they will have lower light tanks and it will be less important.
As I see it You're arguing a largely irrelevant point, what I stated still stands, all lily pipes are largely the same regardless of brand and in my experience from dealing with them you can get best results by mixing brands and using the standard inlets yet even then better results too can be had by using the jbl fluted outlets which produce better flow characteristics in my experience. I say this because I think it's a helpful bit of information for fellow hobbyists not because I've got a downer on anything, I use lily pipes myself on my small tanks and I'm merely sharing what I've found to give the best results. I see no reason to be argue it.