Please, help me identify the filter!

[HowlingWind]

Hi, everyone!
I live in a country where I can't find even the basic water test kits (pH,ammonia,nitrite,nitrate). I've been in several fish stores and they even didn't hear about it, not to mention selling it.
Now I'm also concerned about the quality of the filter they sold me, so please help me identify the type of the filter.

I have recently bought an 8 gallon tank (36 litres = 8 * 4.5, i'm not sure whether it's imperial or US gallons). I also have only the air-pump that injects 1.5 litre of air per minute and a filter that looks like a box that is shaped as a quarter of a pie and suitable to be put in the corner of the fish tank. Filter is filled with cotton-wool-like material and a layer of sand and possibly coal or carbon. It has bars on the top letting the water come in and bars inside leading into the bottom interior of the filter. This interior is connected with the surface by a hole in which I put the air-pump hose with the small blue thingy (I think you call it air-stone since the bubbles come out of it when the pump is working).

What troubles me is this: I have always thought of a water filtration process as something forcing the water to move through the filter and thus cleaning it, and the force of the air bubbles somehow seems impotent to do such thing.

Also, only the top of the filter has started to look dirty, not the interior.

What kind of filter is it (canister, power,undergravel)?
Is it normally operated that way?
Does it contain media suitable for bacteria colony to blossom?
Should I set the air stone deep into the hole or leave it near the surface? does the water flows from top downwards or from bottom topwards?
Should I get the air stone big enough to fill the entire hole?

I'm planning to buy another tank (this one was gift to my girlfriend for our 2-year anniversary). Would it be better to use submersible pump with filter than this kind of filter (girl in the fish store says submersibles are only for big tanks)??

the problem is that even if the filter is inefficient, I will find out when the fish start to suffocate, since there is no way to test the water here.
Please, help.

[e-cat]

its called a box filter, or corner filter. its operating the way its suposed too, the bacteria will grow on the floss and every thing else, im not sure if putting it down further wil do much but it will give more contact time with the air bubble and the water, so it wouldnt hurt.the water flows with the bubble so its going upwards, dont get an airstone that will plug the hole or it wont work properly if at all. with a small tank like that you might not want too put a submersible filter into it because it will take up room, you could go with a undergravel filter and even better would be too go with a aqua clear mini, i would go with the aquaclear mini, you will have good filtration with that, and your store should be able too get it. visit http://www.hagen.com/hagen/canada/en.../basic/1-1.cfm
for some usefull information

[HowlingWind]

Thanks!

[e-cat]

no problem

[justDIY]

one note about your filter.

you need to change the "media" or stuff inside the filter from time to time (every month or so)... Your fish store will help you with getting the correct replacement media.

The white stuff is filter floss. When you replace the media in your filter, save about half of this filter floss, to mix with the new floss. This will instantly seed your freshly cleaned filter with the bacteria you mentioned. Doing this regularly will keep your filter operating in peak condition.

It is a fine filter for a tank your size, combined with regular water changes.

If you're concerned about the quality of your water, leave it sit for a few days where it can get some sun. This will help break down some toxins that might be present, but this is not completely effective.

Best of Luck to you and Welcome to Aquarium Advice!