What do I need to know about filters?

[lolli]

I have a little bookshelf aquarium that came with a HOB filter, and the 10 gal I had growing up had a HOB in it as well. I always just bought the little cartridges called out for by the stock filter, but then I came here as I'm planning to get a 20 gal and it seems filters are supposed to be more complicated...

So I have 2 questions.
1) What can I do to the HOB filter for my 6.6 gal bookshelf to improve efficiency/improve water quality/save money on the removable filters (those standard plastic frame things that hold a fabric pouch full of little black things)?

2) How should I filter a 20 gal? Is there an online guide to filters somewhere?

 

[Big-j]

First off don't remove and replace your filters every month like they tell you too, they are scamming for money, if you replace your filter, the bacteria that keep your fish alive get replaced as well and then you have to cycle the tank all over again, secondly when it comes to filtering a 20g just read whatever filter you prefer and buy one that's good for double the gallons you have so in your case get a filter that could handle a forty gallon

 

[Rosenweiss]

I would recommend (and a lot of others would to) getting an AquaClear filter for your 20 gal. I would get an AquaClear 50, to provide adequate filtration for any species you might choose. THe reason is, they are incredible versatile and you can choose your filter media, not having to rely on little bags. You can stock them with biomax (a great place for beneficial bacteria to thrive), carbon (if your water needs to be cleared or smells bad), or other filter media. It's a great deal honestly. I have two AC50s running on my 29 gallon.

The "black stuff" in the pouch on your 6.6 is carbon. Not bad, but also not the best thing for a tank. To be honest, if you want to save money, don't replace is so often (as you tank will re-cycle a bit every time you do, as you lose all that bacteria). So, just do a pwc, swish around your filter bag in the old water to get the gunk out (not in your tank, in the water you're going to throw out) and just keep using it.