Originally Posted by jrthomas40
i add lugols iodide i belive it is...and a larger water change would probably be a better solution...last time i changed about 30 gallons but didnt want to do much more than that because i didnt want to freak out my fish....my blue regal stayed in hiding after that for about 3 days came back out with cloudy eyes...he is fine now and as are the others but i probably lost about $300 worth of corals and snails....i wanted to replace about 90-95 percent of the water but was told not to cuz that could do more damage but i think it would be ok if i left about 20+ gallons and added some biozyme to help replace the bacteria
In all my experience with tanks (about 15 years and four tanks of my own and about 75 in a LFS) I have no evidence that the water column holds the majority of your bacteria bed. If you read about it you will learn that these bacteria colonize surfaces in your tank. They will die though if you dry them out. (little side note... you cant buy "dry" nitrofying bacteria, its impossible for them to live dry. What you are buying is most likely heterotropic bacteria which are sludge cleaners breaking down detritis and protiens, carbs, etc into ammonia which can then be consumed by the true nitrofying bacteria.)
The vast majority of the surface area is going to be the sand bed and the rock. Keep it damp and you wont kill it during a water change. (at least not unless its a very prolonged water change and you manage to starve it) If you have the water made before hand it shouldnt take very long to do.
The important thing is to do your best to ensure your new waters pH, SG and temperature are very close if not exactly the same. I have no data showing fish and animals going through a Calcium, Magnesium, Alkalinity (as long as pH was the same), Trace element, etc. "shock". Could you create one? I suppose if you really tried to, but normal salt mixes and your tank are going to be close enough even if you are switching to a high calcium salt mix that you don't need to worry about this, IMO.