Mikester, the crabs were the contaminants :roll:
You know that out of all the crabs in the world theres probably about three or four that you would actually want in your aquarium. These are commonly crabs that dont belong to the Mythrax crab species. Basically distinguished by the claws being larger than the head.
If your tank has been running for five weeks i doubt you would have had the chance to see the possible damage tap water can cause. Beleave me RODI is kinda staple equipment. I dont have one, so i drive to the LFS with my 5 gallon drums and buy it. Its not that i like to waste time and money, but its just not possible to run a reef with tap water. And although people say they do, their tanks are testiment to the effects because they all look like crappy cess pools. Ive never seen a good tank run on tap water, so why spend all that money on a reef tank when you end up with a stinking rockpool. You may as well have gone with freshwater fish because i can assure you the results would be far more asthetically appealing. Even if the rock pool/reef tank was crammed with beutifull fish, i still think the look of a balanced system whatever the format is better than one thats failing miserably. The only possible exceptions to tap water is, as has been mentioned "virgin" water, or well water from a relaiable source, but even then an extensive ammount of filtration and de-ioniseation still has to be done. The RODI doesn't even need to be expensive to be affective in producing a reasonably pleasant reef tank. But to get it looking better is only going to mean more effort on your part. Starting a reef with tap water is like starting a marathon by blowing your leg off, yea its possible, but you'd have to be some kind of twisted sadist to want to attempt it, and a geneius to pull it off, and allthough i loosely fit both categorys id still point and laugh at seeing someone try (except in this instance where help is defenately a more constructive approach). :twisted: