Wow, there's a lot of differing opinions here. By the way, I'm a night owl because I'm on call from 7PM to 7AM half the nights of the year, including weekends, so that's why I'm always on really late sometimes. If it's slow, there's not much else to do (can't mess around with my tank at 4AM, and can't mess around with power tools anymore either cause I have a baby that I don't want to wake up).
Back to coralline algae, I was not aware that coralline algae used up nitrates. Although I always knew it was an algae, I never put 2 + 2 together (it equals 3, right?). I was always under the impression that coralline algae used calcium and iodine and some trace elements to build itself and grow, never thought of nitrates. Anyway, back to the discussion. The main reason I ask is because I'm very curious about how it can affect our little ecosystems. Obviously, coralline does not grow in the dark, so the underside of our rock is usually exposed versus being encrusted, but I wonder how much water can actually flow through coralline algae. Has anyone ever looked at it under a microscope? I know that coral skeletons are very porous, as they are more or less a maze of tiny fissures and pathways, but does coralline algae share the same structure? It obviously has no polyps to extend, so I would think that the pattern we find on most corals would not exist. Ever try looking through coralline? The light gets through it okay, but what about water? I wonder about these things as people lament the fact that their rocks are not covered in it (mine aren't either, although portions of it have coralline growing on it). I know one of the benefits is that algae has a hard time establishing itself on healthy coralline, but what are the other real benefits (not including aesthetics)? Someone has suggested the nitrate consumption which is news to me (not being sarcastic, I just never thought of it as a true algae), but what other benefits are there? It doesn't house bacteria, does it? If it is very dense, then wouldn't it be like buying crappy rock that is very dense? The measure of good live rock is how porous it is as far as filtration is concerned IMO, so how is very good porous live rock affected by being heavily encrusted with coralline?
Where's Jack Handy with his deep thoughts to join me at this late hour.....
