Sorry to revive this old thread but frankly, this and your pressurized CO2 thread, are the two absolute best primers out there.
On topic, I was very interested in your explanation about how the WPG has fallen apart (not to mention LED being a completely different bag). Simple question: How does the single 13watt CP over my Fluval Flora (basically a 12" cube) rate? I'm guessing "low light". Would a second one take me up to "Medium", or would that be getting towards what would be considered "high"?