uxcell XINYOU XY-380 Aquarium Fish Tank Biochemical Sponge Filter, 4-1/2-Inch (1-Pack)

Nice and cheap and very modular so if you wanted to make a monster filter, you could just pull these apart and build one that was 2, 3 or more foam high. Got a tank that is 5 feet tall and want a monster foam column in the back? Just buy a few of these and make your frankenfilter. Just remember to get a pump strong enough to drive it. Now for the people who are worried that it doesnt come with an air stone. All you do is GENTLY pop apart the filter and then grab a few things. You will need some cheap air stones and a little bit of aquarium tubing. Once it is apart you clip out the tube from the bottom section (you can feel free to clip the bottom grill that holds the tube) so there will be space for the air stone. When you are done you should be able to stick your finger through the bottom piece without issue. Once you have done that cut a short ~3/8 piece of aquarium tubing and place it in the bottom of the top part so the air stone will have a sung fit. You could also glue the air stone but then how would you chance it when it plugs up? Once you have fitted the air stone and made sure it is snug reassemble the filter. The picture should give you an idea if these instructions were confusing. If you want to use one of these as a prefilter for a canister or HOB (Hang on the Back) power filter price compare the foam refills as you will not need the internals.

no air stone to replace. Which I thought would be nice, but was unable to control bubble size to tune water movement.

My favorite aquarium filters. Have bought many of these.

Much larger than anticipated but well worth the investment.

Works well in all my breeder tanks and is great for the price.

Would buy again

Standard sponge filter, works just like it should.

Easy to assemble, does the job.

The is a really good sponge filter at an every better price than anywhere else. I use it for my breeder aquariums when raising newly hatched baby fish fry, as other filters will kill the new baby fish. Works well and the sponge contains your bio.

its a great product added it to my 55 gal African cichlid tank for extra oxygen and flow and it is working great, I would recommend it to anyone with a 40 gal and up