Tetra Bio-Bag Ready-to-Use Disposable Filter Cartridges for Aquariums, Medium, 4 Count

Love these you get 8 instead of the 3 pack you just have to put it together not hard at all

Best around, only one that works. Great price at the moment.

I've tried other filters and these are the best. great value

Not much to say about them. Same bags we've been using for many years, just much cheaper to buy in the big 12-pack box. You're going to use them sooner or later anyway. Why not save some cash?

These come unassembled so you save money. It is not difficult to put this together. These bio-bags work very well. This is my first use and I like them and like the savings even more.

highly recommend

They are cheap and simple to use. I like them cause they do a great job on filtering my fish tank without costing me a fortune.

With just a little extra work, you save a lot of money. with 12 pack, it is cheaper than 3 assembled package.

I didn't realize that this was the type of filter you had to assemble. I missed that in the description. Having bought the assembled ones before, I can compare and contrast the difference. The assembled ones seem to leak carbon unlike the unassembled ones. The unassembled ones are more worth the money because they are cheaper and they are easy to assemble. They work just as good as the assembled ones. However, these filters don't last long. I would replace them after one month or sooner if using them alone. I use these along with a bio sponge to increase the effectiveness of the filtration. Overall, they do the trick because there isn't much competition.

I purchase 2 boxes Tetra Bio-bag ready to use disposable filters cartridges and I received 2 boxes of Tetra Bio-bag unassembled disposable filters cartridges . So I will be returning them. I also noticed that someone else had the same problem. I guess I'll have to read the reviews more carefully before making a purchase from now on.