Cycle question - let there be light? or no?

[rachyl756]

When I originally set up my 90, we cycled in the dark. a good long cycle in the dark. I think we went 3 months before adding the first snails.

Now I see some people cycle with lights, some with limited lights and some with no lights. What are the pros and cons?

Also I find alot of conflicting info about water changes during a cycle.

Thanks

[tdwyatt]

Everyone has an opinion about whether or not to treat the live rock an a live animal (so you'd need water changes and circulation and skimming and light...) or as an inanimate biofiltration medium that needs to be purged of any potentially bad hitchhikers. If you're re-curing old rock and there is little stuff to be concerned about in terms of hitchhikers, or it came from a high nutrient system and the rock has to "cook out" some of these nutrients, then there is no reason to do anything but to change the water and remove the detritus once a week and maybe skim if you have the equipment laying around (so you'll still need good circulation and to export detritus as often as is reasonable to remove it from the rock.) If you just bought new rock laden with any number of desirable benthic and epibenthic flora/fauna and you'd like to save as much as is possible, then you're going to need to think of each piece of rock as a live animal, requiring low ammonia, high oxygenation, and waste export (heavy skimming and frequent water changes) as well as a source of light adequate for the task at hand.

So, it depends on the source of your rock and its intended use.