[Ron Reefman]

rfurst, I'm not looking to start an argument here. And your list of things to consider is pretty inclusive, some of your points are very well taken. Some are really almost unimportant, but that's just my opinion. But the very first one on your list is confusing.

I know full well what PUR is and how it's different than PAR. And I'll even agree that PUR is more important. However, how do you know what the PUR is for any given coral? They all have different kinds of zooxanthellae and therefore have different light requirements (or PUR). And then just what tool do you use to measure PUR? I've never seen a PUR meter. So if you can't really identify the PUR for a given coral, and there is no tool or meter to measure PUR, why make life so confusing? It's an important concept to understand, but if I don't know what the PUR is and I can't measure it, it really should just be a footnote.

We know the 400nm to 500nm wavelengths are the most important for most coral's zooxanthellae. Isn't that enough understanding about PUR? And you are right about PAR meters reading all light (not necessarily equally as blue is somewhat under read). But at least there is a meter that can give you a number to work with. So why would you say it is of limited value? To my way of thinking, it's better than the value of the non-existent number you get from the non-existent PUR meter.

Again, I agree with you that PUR, if it were something we could know and measure, would be much more useful. But we can't, so why confuse people who are just getting started. You make it the number one thing to consider, yet nobody lists any PUR numbers for their fixtures, or for any corals you buy. So how is that the most important criteria?