external filters?

[thisisyesterday]

tell me more about them

was on a fishkeeping forum earlier reading an old thread and they seemed to reckon that there wasn't much difference between internal/external apart from external need cleaning less often and are easier to maintain?

in terms of flow round the tank is there a difference? i have a 3ft tank and i don't want to make the wrong purchase here!
will an external filter keep my tank cleaner?

also, i think my tank is approx 108 litres. some of the external filters are banded up to 100 litres, then up to 200 litres

would i need to go for the up to 200? obviously i don't want anything too powerful...
will have sand in the tank, and real plants

[EauRouge]

You can't overfilter a tank so don't worry about that. You can arrange the spray bar so the flow is not too powerful but most fish will love it anyway.

The main difference is that external filters are outside the tank and internal filters are inside so external ones will use a bit more power because they have a more powerful pump but because they are bigger you get more choice of what you can put in there (most have ceramic media like bioballs) instead of just sponge. Don't bother with carbon though, you have to change it every 20 seconds and it's not needed in a healthy tank especially if you've got real plants.

I would go up to 200 litres, you're looking to turn over all the water in the tank at least 4 times per hour so check the litres per hour rate on the filter.

[thisisyesterday]

ahh cool thanks! am watching a few on ebay so hopefully can get a bargain

[thisisyesterday]

if a filter comes with carbon and sp-onges etc can i swap it for ceramic media?

[EauRouge]

You can put in whatever you like but it's best to have (from bottom to top) ceramic media, course sponge, more ceramic media then fine sponge or floss.

The main types of filtration are- mechanical filtration (sponges) physically removes bits of poo, biological filtration (ceramic stuff and also sponges) is full of good bacteria to get rid of ammonia and nitrIte), and chemical filtration (stuff like carbon and also protein skimmers) is not really needed for freshwater but is mostly for marine geeks . All filters need at least mechanical and biological filtration.