Keeping marine fish

[Miss Zippy]

I'm looking into setting up a marine acquarium (intending to keep fish and a few 'fire' shrimps). Are there any experienced marine fish keepers who can tell me whether it is crucial I use water that has been subject to reverse osmosis, or is untreated tap water ok?

[WendyW]

I kept marine fish years ago and I found that no matter what I did they died within a short space of time. I read every book I could find and tried all sorts of things but in the end I just gave up and whet back to tropical fish. Hope you have more luck than I did.

[wildwood]

From a somewhat rusty memory on the subject, the quality of tap water is not important. I presume you are planning to use packaged salts to add to the water, rather than using natural seawater. Whatever, you have to wait about a month for the nitrate to turn into nitrite (or the other way around) before you can add any fish. The type of gravel is very important and filtration is crucial.
I did manage to keep some alive for up to two years, but there has to be a constant vigil for introducing potentially toxic substances such as to much food (shrimp etc) which can quickly go off.
If you are serious about setting up a marine aquarium you should really read some good books on the subject and be prepared to spend considerably more on good filtration equipment etc. than the actual fish. It is a struggle but the joy of looking at a successful setup is a joy to behold.

[ColinV]

Yes most certainly, RO water is a must, and a basic unit can be bought quite cheaply. Tap water no matter what anyone else will tell you is bad news, all sorts of chemicals are in it, even very small amounts of copper are lethal to inverts and some snails, phoshates will cause you all sorts of problems. With Marine, read, read, and read all you can get, research and planning is a must, and if you follow the advise, use the right equipment and put the time in escpecially for the first six months, you will be ok. Come back if you want any specific further info

[Miss Zippy]

Thanks ColinV. Since posting this question, I set up a marine aquarium after doing lots and lots of research and picking the brains of users of sites like Reef Park. The tank has been running for about 18 months now. You're right that it can take 6 months for your system to become fully established and I have used RO water from the very start.