Hi,
As I stated in this month's [rk] article, I think the best thing we can do now is to use filters such as Polyfilters and GAC to remove as much of the these trace elements from the water as possible when we make it up. I have been discussing this with the manufacturers of the Polyfilter, and it is possible to lower the trace metal concentrations below toxic levels in this manner.
For those of us with older tanks, I suspect it is time to "start over." This means to break down the tank, get rid of the contaminated live rock and sand, and rebuild anew. Then use only - ONLY - filtered water until such time as a good salt mix becomes available (and that may only be a month or so off, - I have also been talking to a salt manufacturer who has a product that may fill the bill).
Remember - the accumulation of these materials is not just in the sand as precipitates, the accumulation as adsorbed matierials will also be in/on the live rock, and on EVERY surface in the aquarium, including inside the plumbing, etc.
Now, lest you think that this is all an "academic" exercise for me, and that I am simply pontificating about an unexperienced theory. Here is some background. My lagoonal reef is now 7.5 years old. It worked well for about 4-5 years. Then I started to get "odd" random deaths, eventually one by one all my stony corals which had been growing well, died. No obvious causes were noted, I didn't change anything, in either my procedures or materials. Eliminating all other possibilities, I began to consider seriously the idea of toxic chemical accumulation in the system. That is when I started these projects (the Tank Water Project, The Tank Export Project (yet to be reported on, etc.). I found my tank (and other older tanks) to have high levels of these poisons - even though I never dosed any of them.
The toxicity of the water is not in question. Tests have been done showing that sea water with concentrations of copper, nickel, vanadium, zinc, etc., lower than what we have in our tanks kills some corals, snails, and other animals. We know from basic physiology that those animals that are not killed are stressed and prone to death from other factors.
We also know from basic chemistry that these trace metals adsorb onto surfaces and can predict pretty well what will happen to them if conditions change.
So... you may consider the idea of tank mortality due to toxic chemical build up as a theory. It isn't. I have collected the necessary data, and I have done the necessary tests to show that it is a proven fact. Over the next month or so, additionally I will be doing some direct sea-urchin larval bioassays on various of the salt mixes to put the last nails in that coffin.
So...
My lagoonal reef's days are numbered - to maybe about 10 days to go... I have some live rock curing and when it is cured, my old setup is history. I will break down the tank (saving what livestock I can), decontaminate it with a series of muriatic acid rinses, and re-establish it with a deep sand bed and new live rock.
And I will not ever use unfiltered or old salt again -ever. If I need to, I will make my own salt mix.
And I would advise you to do likewise.
