Thanks all. I have fairly hard water where I live as well if that helps.
So if I get a 125L tank with a canister filter, 2 clowns, a wrasse and some shrimp and snails, would that be ok? Anything else I need to know?
You mention hard water... I wouldn't be using tap water for marines, certainly not if you want to keep corals. There's a shed load of stuff in there that water conditioners just don't remove... ok in FW as plants will use it up, but will just fuel algae in marine.
Use RO... for a newbie and a smallish tank, is just buy a couple of food grade 25l containers and fill up with RO/DI water at the LFS... costs next to nothing on a small scale.
You'll need a decent size bucket to mix salt up also... if your LFS sells it, you may be able to just use already made up saltwater. As time goes on, you might even want to move to natural seawater (NSW) depending on how far from a clean source you are.
Canister is great, remove ALL the stock filtration media and replace with carbon, phosphate remover and maybe a bit of polyfilter... that will all help keep the water pristine. Remember all your biological filtration will be done by the rocks, not the canister, so just put media in there that you'll bin and replace on a regular basis, that way you won't end up with a build up of nitrates and phosphates, which again will fuel algae growth.
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