[ttran1130]

Ok guys, my brother just gave me his 125g tank and thinking about turning it into a saltwater setup. It was a fresh water set up and I was wondering if a canister filter will work for salwater? I'm a newbie at this so any suggestion would really help.

[demonsquirt]

A canister has its place but in the right hands. But not needed and can actually add to poor water quality. In a salt water tank your LR and LS are your best bio filter.
For a new setup you need a quality water source and powerheads for water flow and LR and LS at a minimum of 1 lb per gallon. Though you dont need all LR you can get a little LR and then add base rock which will become live. Then a skimmer and lights. Then your tank needs 4 to 8 weeks to cycle. I would get a book and research the whole setup and cost before you start.
A 125 with the basic equipment will increase your monthly electric bill 30 to 60 bucks alone then there the salt and water that add up. So you could be looking at around 100 bucks a month just to maintain its normal requirments. A book would be a great start. GL..

Amazon.com: The New Marine Aquarium: Step-By-Step Setup & Stocking Guide: Michael S. Paletta, Edward Kadunc, Scott W. Michael, John Goodman: Books

[ttran1130]

Well I figure since the tank came with the canister filter that it could be used. Thanks for the useful info. keep 'em coming.

[demonsquirt]

It could be used but with no stock its just useless and means more maintance and extra electric. If you use dont use any media besides some carbon and some rubble rock. Then in a new setup there are so many things that can go wrong eliminating its use as a source can very usefull. This isnt needed for coral and with 2 or 3 fish your LR will be fine.

You need to learn the basics and there care before adding these things.

Like i said you can use it for removing any fine debris thats kicked up but dont use any bio balls or other media. Just use some foam or mesh media and keep it clean .

Basics being RO or better water source.
Powerheads for water movement.
Atleast 1 lb per gallon of LR and LS.
Skimmer and lights.
Water test kits.

IT will take weeks for the water to cycle and in this time you can research your CUC and wanted stock and there needs.
Slow and easy is the key for any long term succes.
You can throw together a tank and it will seem fine for awile , from months to yrs then have problems. By this time if you dont understand the basics you will just think you need some reactor or other add on that wont work.

Like the Oxygen level in your tank. Your water recives its O2 from a surface exchange or a gas exchange at the surface. And with low stock then the O2 level if low wont be noticed.But as you add stock they take from this and if O2 isnt enough then you will see trouble from PH problems to dieing fish to poor coral. Then low flow can effect your PH levels. But this could take time.