Fluval vs Aquaone filters

[polerz]

I need another 200L worth of filters. I have a 640L tank and I am unable to use a cannister filter as I have no where to put it. I have already two internal fluval 4 power filters running with only 4 fish in there. Its a new tank so I think I have a little bit of time before I need some more filters?

Questions:
a) how much time do I have? The ammonia is at about .25-.5ppm (but its a new tank -around 3 days old- so thats acceptable atm.). PH is spot on.

b) The two fluval 4s will cover the filtration needs for around 400L of the 640L tank. So I need another 1-2 filters to do the rest of it. I was looking at these:
2 of these:
http://www.theaquariumshop.com.au/shopexd.asp?id=189

or the much more expensive fluval ones (around $89 each).
1 of these:
http://www.theaquariumshop.com.au/shopexd.asp?id=386

My question is, whats the difference between the aquaones and the fluval. I mean they are a simple design, sponge, bit of air pumping water through the spunge.

Am I right with the aquaones? Or should I spend the extra money and get another two fluvals ontop of the two I have.

c) Are there any differences between internal power filters like the ones above or external power filters like: http://www.theaquariumshop.com.au/shopexd.asp?id=372

Thanks alot guys

p.s. the tank is cold water, I have about 4 gold fish in there.

 

[trotty]

Depending on what you plan to put in the tank, my rule of thumb is to circulate the tank at least 3x an hour, more with high population/big fish. i have used other aqua 1 products and found them to be reliable. go with what you can afford. if its goldfish, just use the aqua 1's.

 

[Zagz]

Goldfish are very messy. They tend to need extra filtration IMO. I am unfamiliar as to what is available to you at your lfs's but what about a decent HOB filter? For $89.00 here one would be able to get a decent filter, but as I said I have no idea what your pricing is like and what is available to you. I can't get half the things people from the US can get here in Canada.

 

[trotty]

i have an AQUACLEAR 500 amongst other filtrs on my 8x2x2 ive never had any problems with it, good if it doesn't get in the way of your hood. i've also used the aqua 1 hob's and found them to be just s reliable. great water flow on all, you can get a bit of noise if the tank is not full, or at least to the bottom of the filter.