Water changes

[Quagmire]

Originally Posted by justinl

Q, yes, a single area of a few gallons in the ocean does get a 100% change many times a day, but that is not a rational comparison due to scale. it's like taking a look at one cubic centimeter of our tank and saying, that it gets 100% water change numerous times a day within our tank. but a change with what? the same water that was previously occupying it. so really, nothing changes. i suppose you could say the ocean is a small tank with a near infinitely large sump... which obviously cant compare to a closed system tank.

I don't think the comparison is off at all,assuming you have parameters in check.Say in the ocean a clam dies,the current replaces the foul water around the clam which dilutes and dissipates.Althogh the replacement water come from the same body of water,it is fresh and clean,where as the old water was foul.If you are using the same salt,mixed to the salinity,at the same temp and PH,for a water change,then it is no different than what is in your tank,only fresh.
I'm not saying the w\c will fix the problem,if the above dead clam was in a tank you would have to get it out or the tank would foul again.
But the w\c in itself won't cause a problem,aside from the possible light shock mentioned in my first post.