Hi everyone. I just joined this site today. I recently got my first aquarium, a 20g hexagon on Feb 21st, 8 days ago. The tank is about 18 inches high. It came with an Aquaclear 20 filter. The inlet tube on it is only about 6 inches. I am wondering if it is long enough for such a high tank. I can see very fine particles in the water which give the water a slightly cloudy appearance. I also wonder if they are too fine to be picked up by the filter. Does anyone know or would they reccomend a different filter for me? As far as fish go I only have 2 mollies in the tank right now so there shouldn't be too great of a load on the filter I wouldn't think. Thanks for any advice.

I'm not sure what the specs are for an AC20 but with a hang on back filter you want one that will move about ten times the volume of the tank per hour. So you will want a filter that moves about 200 gallons per hour. The white you are seeing could be a bacterial bloom which is a sign that your tank is cycling.
Are you familiar with the nitrogen cycle? If not read up on it. Aqua Clear makes a great filter so it should be working fine. The important part of the filter is so get a bacteria colony established. The bacteria growing in the filter will convert the toxic ammonia and nitrites into nitrates which are not as toxic to fish. Any stuff that your filter does not get should be taken care of with weekly water changes/gravel vacs. Since your tank is only a few days old it has not cycled and is not 100% safe for fish yet. You should have a good test kit and you should be doing water changes whenever the ammonia levels start to rise above .25 ppm. Once cycled the ammonia and nitrites should stay at 0. As far as the actual length of the tube it wouldn't hurt for it to be longer but IMO its not a huge deal that it is short. The AC 110's that I have come with an extension. I am sure that somebody on here knows if these extensions are compatable with the AC 20's. Also until your tank is cycled I would not vacuum the gravel when you do your water changes.

Thanks for the reply. I have read up on the nitrogen cycle and I have a test kit. I had them test my water at the pet store tonight too. My ammonia is at 0 and my nitrites and nitrates are very close to 0. I put stress zyme in to help establish the bacteria. The girl at the pet store thinks that has helped and is why I'm not seeing any ammonia. I put some accu-clear in tonight and in a matter of a couple hours it has cleared some. As for the filter I read that it should turn over the water 4 times an hour. Mine is rated at 100gph. Is more better? Can you use too powerful of a filter? I am gonna keep testing the water every two days.

You should typically get twice the amount of filtering for the amount of gallons you have. Thus, you should get a filter that is meant for around 40 gallons. I would recommend you either find a way to exchange your 20 for the AquaClear 50, or perhaps buying another AquaClear 20.

Keep in mind that you don't need to throw out the sponge and biomax the AquaClear comes with. Just rinse the sponge in a bucket of the dirty water you siphoned out when you do water changes. You don't want to rinse it out in the sink/etc because the chlorine will kill the beneficial bacteria that would be living in it. Same goes with the biomax.

You can't really have too much filtration unless you are blowing your fish all over the place. What type of test did the store use to test your water? Test strips are notoriously innacurate. I would get a good liquid test kit and do the testing yourself. I don't know a lot about stress zyme but most additives that are supposed to cycle your tank will not work for you. They will actually keep your tank from cycling. The bacteria in them is not aquatic so it will only last a week or so and you have to keep adding it. The problem is that the additives will consume and process ammonia however your filter will not establish a good bacteria colony on its own so once you stop adding the additives you will have problems and a tank that is not cycled. The best advice I can give you in the beginning is to do all your research online. Once you find out what you need you can then go to the pet store to make purchases. In most cases taking advice from some part timer at a retailer will do you more harm then good. There are a few good ones out there but you have to remember they are in it to make money and a lot of them don't really know this hobby like they should. Just my opinion but I think most will agree with me on that.