Thoughts on external canister filters

I have a 3 ft tropical tank (30 gallons or I think around 144 litre). No special fish, just the average mix of peaceful species...pleco;cats, guppies, neon & black tetras, swords, headlights & clowns. I feed them a mix of wardley flakes & a lot of bloodworms.I get a lot of baby livebearers that I pass on to friends etc I have an undergound filter with a 'hang on filter' which is a few years old & doesn't seem to be doing much of a good job lately. I'm thinking of changing to a canister filter & have had varying recommendations. I was advised that a Sera 1100 would do the job & would only need cleaning every 6 months. Someone else said a Eheim would be cheaper & better. Other advice was to get an Fluval (unsure of the model) Any ideas which would be the best for me, I want to spend the least amount of time cleaning filters out!

BTW I live in Sydney, Australia - so would need to be able to purchase the product locally. Thanks in advance for any help you can give me.

I have a 20 gal tank for about 12 years now. I use an Aqua-clear 200 hang on filter that I clean every water change. I also have a Fluval 103 canister that I clean about every 4 to 6 months. My hang on filter only has a sponge and a bag of peat pellets. The canister only has the ceramic 'nuts', a sponge and floss. The canister never gets clogged because I use an Eheim surface skimmer for the intake. All seems to work well for me.

I summarized some info on filters here. http://www.2cah.com/netmax/basics/filters/ filters.shtml The choice between powerfilters and canisters is partly maintenance related (preferences), quality & flexibility (canisters) and not having external hoses (powerfilter).

If you find that your current filter is not doing the job, then more or larger filters are a good idea, however it's also a good indicator to check on a few other things. Your fish load has increased (more and/or bigger fish eating more and creating more waste), so you want to be sure that the tank's pH equilibrium is not shifting (easy to check by comparing your tank's and tap's kH and NO3). An excess of nitrate (NO3) or an acidification (low pH) due to a low buffer (2 or 3 dkH) is a common occurrence with older tanks and increasing fish loads (research old-tank syndrome). It's mostly caused by an accumulation of plant and animal matter decomposing in the gravel.

Another caution is that your filters are holding the bacteria which are keeping the fish alive (detoxifying the water), so don't change all your filters to add a new one. They will need to run in parallel for a while to cross-seed the bacteria, or you need to move the aged filter media into the new filter.

There are several posters in rec.aquaria.freshwater.misc from your part of the world who could advice on locally available equipment. good luck

An Eheim is higher quality than a Sera, although I've only had one Sera.

Thanks I'll definitely try these.

Fish4U are very good, and there prices take a lot of beating