Going to play devil's advocate a bit here... Not only is stability not that ONE thing. It's not even all that important and has been blown out of proportion as to how important it is to success in this hobby for years...
Stable water temp? Not very important, I've watched my temps swing like mad, randomly and dramatically at times. I've done large water changes while dropping the tank temp by 5f while not seeing a single sign of stress. There's nothing stable about water temps in the natural environment for these corals. It is important that they swing within a range though.
Alkalinity... I see alkalinity swings get blamed for a lot of stress and problems in corals. When it happens in an otherwise healthy system it often results in no changes, for better or worse, and no outward signs of stress in corals.
Magnesium, I've boosted it 800+ PPM in a matter of seconds and the corals didn't even react. THe same goes for bumping calcium by bover 100ppm.
Could go on and on, and the examples above are from tanks where corals have fast growth and very good color.
Hi Ike,
Very good points, and I appreciate the feedback. I agree that in a well-managed system, uber stability may not play as critical a role as some people think. However, in many tanks, multiple environmental parameters are subject to fluctuations, and this is a recipe for problems. I will have to respectfully disagree about the alkalinity issue not being a problem...We've seen this first hand in our facility on several occasions be a direct cause of issues, such as color loss, etc. Yes, alkalinity drops may accompany other factors, but it is definitely an issue for many systems. That being said, you're right pointing out that we can't implicate lack of stability for every problem in our reefs. However, it's a very, very, primary factor in success. Yes, corals can "tolerate" a lot of abuse and variation, and it can be argued that some reef systems in the wild undergo tremendous temperature, etc. shifts in the course of a day during tidal swings, etc. However, these are "open" systems with the benefits of such. A reef tank is by definition a closed system, and chemical and other environmental issues have much farther reaching implications than in the wild.
Sure, many corals can recover nicely from fluctuations, and can even tolerate some. This does not, IMHO mean that we should accept unstable parameters or encourage lax husbandry protocols. I can recover nicely from being spun at a high speed on an amusement park ride, but that doesn't mean that there won't be some stress in the longer term coming from the experience if it happens with some degree of regularity. Probably not the greatest analogy, but you get what I mean.
In the end, obsession over any ONE thing is not a healthy approach to reef keeping. Obsession over providing a stable, well-managed environment IS a healthy approach, IMHO. That's whey we have a marketplace crowded with tons of cool equipment, additives, etc...To quote my friend and local SoCal reef guru, Greg Carroll, "StabilityPromotesSuccess." I can't really argue against that.
-Scott