Very confused about filters

[kirty]

I bought a second hand 4ft tank (approx 120L) that came with an AquaClear 300 filter. I found the filter online and it says its suitable for tanks up to 375L (this is the filter http://www.aquariumproducts.com.au/catalogue_products.php?prodID=2887&catID=4 ). I went to two aquarium shops today to buy some plants and backing, and at one place I was told I also needed an under-gravel filter, and at another place I was told I had the completely wrong filter and needed to buy a big canister filter or use an Eheim filter as well! The second place also said that under gravel filters are crap. I'm feeling very disheartened now and don't know what to do. The filter seems to be working well and the water is certainly moving around in the tank. I also have a small air pump with one air stone in the opposite end of the tank.

Does anyone know if my filter is OK? Any advice?

[Yanagi]

I wouldn't use a HOB as the primary filtration on a 4ft tank. If your tank is understocked then you will probably get away with your current filter but I think you're better off with a canister. You can put a lot more filter media in one, especially biological media. You could easily go for an aqua one 550 or eheim classic 2213 (ehiem has far more and far superior filter media included) and continue to use the aquaclear.

Undergravel filters are outdated technology IMO, but alright as a supplemental filtration in a non-planted tank.

You don't need an air pump. Your HOB filter is doing the exact job that an airstone does by creating surface movement.

[kirty]

Thanks for your reply. Does it have to be a canister filter? What if I put something like this ( ) at the other end of the tank? I am planning on keeping the tank fairly lowly stocked, so I think I'll see how I go and buy a new filter when I can afford it in a few months.

[Spanger]

No advice - just want to nod my head in support of your confusion re: what filter you need. It's actually far more confusing than I ever thought it could be :D

[zhong89]

I agree with Yan, a canister filter is so much easier for a 4ft tank. A undergravel filter is no good if you're trying to grow plants in the gravel (sounds like you are) not to mention you have to clean it regularly if you want it to work effectively.

I would recommend you don't bother getting another filter in the meantime and just save up for a canister filter. I've used the ehiem 2213 and the fuval 204 and I highly recommend the ehiem. It's the easiest to use and most effective by far.

In the meantime keep the tank under under UNDER stocked, since you've just bought the tank so you would need to cycle it anyway so go easy on getting fish.

[Yanagi]

You don't want an internal filter, you want something that's going to hold more biological media which that ehiem internal doesn't. For the size you would need it's only about $30 cheaper than the 2213 canister, anyway. I have that ehiem internal and while it's a good filter it's got nothing on a canister.

[kirty]

Thanks again for the info. I think I'll just go steady with the fish and save up for a canister. I was trying to avoid an external piece of equipment, because I have small kids and lots of cats! LOL! Might have to turn my stand into a cabinet to keep fingers and paws away. ;)

[fishbites]

Here's a few thoughts on the various filters available - for your situation, I'd hang on the Hang Over Back filter till I worked out what type of fish and how many you are going to stock the tank with. The HOB filter will be a good second or backup filter so hang onto it. A canister would be good for a 4ft tank but a sponge can do the job just as well if you don't have too much debris to remove (this can be taken care of by using a gravel vac regularly anyway). The sponge can't do much of a job with chemical filtering but the HOB can be used for this and the sponge for bio filtering... just a few thoughts and keeping it cheap as possible for you....

Other filter options include:

Hang Over Back Filter - mid price option - depending what media you fill the filter with as to what you can do with it - quite versatile - easy to see when it needs a clean, provides good surface agitation. Great as an additional filter if overstocking for a short while. I run mine with pure sponge but can put carbon bags or macropore bags or whatever in when I need it just by lifting the lid. For a few fish in a 4ft tank it should be fine....Lethal to tanks with small fry unless intake is covered with sponge (reduced water flow as a result). Can have inline UV steriliser connected to its uptake tube if required.

Undergravel filter - cheap option - not suitable if attempting a planted tank (roots get down and tangled in filter plates). If power goes off can be fatal to fish as it stores all the "bad gunk" under the filter plates in your tank. No good if you have cichlids (they dig too much and expose the plates). For a general fish tank though, an undergravel filter is cheap and can run for a long time before needing to be taken out and cleaned up. Provides great aeration and safe for tanks with small fry.

Canister Filter - expensive option (especially if buying 'big' name brands) - sizes to suit most tank sizes from 2ft up to 8ft - can be filled with variety of media - often has water flow capacity listed as maximum without media so watch out for getting low flow filters for larger tanks (1200l/hr empty means you'll be lucky to get about 2/3 of that with full trays of media). Has spray bar or normal pipe return options. Fatal to small fry unless strainer covered in sponge (reduces water flow as a result). Can be a hiding place for a snail factory if Malaysian Trumpet Snails or Ramshorn Snails get into the canister. Can go several months between cleanouts. To clean requires taking off the canister cover (including motor, taps, etc) and cleaning it out - larger volume of media means a big cleaning job compared to other filter types but only has to be done every couple of months. Provides great water flow. Can have an inline UV steriliser connected to the pipes if required.

Sponge Filter - cheap option - good for bio and limited chemical filtration - sizes to suit the smallest spawn tank up to 1000 litre tanks - requires an air pump to run. Can provide plenty of surface turbulence to help oxygenation of water. Fry friendly. Easy to clean - just squeeze out in a bucket of drained aquarium water once a week during water changes. I run 1 x large sponge per 2 to 3 foot tank and two of them in a 4 foot tank with no water quality issues.

Sump - expensive option - plumbing alone can cost more than a small canister filter! Plus the need for a 2 to 4 ft tank (depending on size of main tank) housed underneath. Can be run wet or wet/dry and can turn over huge volumes of water. Great for water turbulence, mechanical/chemical/biological filtration. Downside is that most sumped systems require drilling of the tanks to install bulkheads or standpipes. Overflow boxes can be used instead but can be costly and noisy in operation. One sump can filter many tanks and saves on power by using only one pump and usually one heater. Downside is that all fish are in the same water which has implications for disease control and water condition requirements for different species. A UV steriliser can be run in the sump to control diseases and algae if required. Can be fatal to fry if caught by the overflow. Some fish can be held against the overflow and perish if water flow too strong (suggested best for stronger / larger fish - definitely not guppies).

Top Filter - mid priced option - a small pump pumps water from the tank up to a "box" located above the tank - water passes through filter media and drops back into the tank at the other end. Very easy to construct on a DIY basis - plastic tub / pump / bit of pipe / filter media and Bob's your uncle!!! Literally an above the tank version of a sump but without the ability to service several tanks and without the capacity to use a heater / UV steriliser in the filtration chamber itself (must be put in tank if using a top filter). Can be fatal to fry if sponge isn't placed over pump uptake. Provides good aeration of water.

Internal Filters - mid priced options - essentially a high water flow pump with a chamber under it with sponge and sometimes other media - great for water circulation in a large tank but provides minimal useful filtration (either mechanical / chemical or biological). Useful only for large tanks where you want good water movement. Some have a venturi system which provides some surface water turbulence to help in aeration.

[kirty]

Thank you so much for all of that info! Do you have any links or brands/models of sponge filters that you would recommend?

Edited May 29, 2011 by kirty

[fishbites]

Try your LFS (you save on postage costs then) but otherwise Ben at Age of Aquariums stocks a range of sizes of sponge filters - click here