AQUANEATAquarium Bio Sponge Filter 4 PCS 20 Gal Breeding Fry Betta Shrimp Fish Tank

I'm 49 and have been an aquarium hobbiest since I was six. My local aquarium store manager talked me into a sponge filter after years of using underground, canister, and hang-on filters. The 4-pack deal on these was just too hard to pass up. Currently running one as my sole source of filtration on a 29 gallon stocked with approx 30 fish--10 each of Tiger Barbs, Serpae Tetras, and Zebra Danios.Ask yourself, why do fish stores almost universally use sponges on their tanks, entrusting hundreds of thousands of dollars in fish inventory to their operation? Answer: It's the only system that provides fantastic biological filtration in a simple, bulletproof design. Power goes out, your $500 canister filter doesn't come back on, and the clock is ticking on your fish as the oxygen quickly starts to dissipate. The biological filtration on a sponge never goes off. Your fish can survive for days, even weeks if the pump is tripped.Second question: Then why aren't sponge filters more popular in the aquarium hobby? A sponge filter is a single component joined by a tube to a pump. The filter, tubing, and pump (plus an air stone and check valve) will set you back about $20 and last for years. A canister filter costs anywhere from $100-$500, has about 50 parts that can break, and requires regular maintenance and/or replacement of the filter and media trays. Plain and simple, sponge filters are not popular because filter manufacturers can't make money off them. Why would the manufacturers and by extension pet stores try to sell you something you'll NEVER need to replace?A few words about the negative reviews. One guy says they never sink. FALSE. Drop it in your tank, let it soak for an hour, then reach in while the sponge is submerged and give it a good squeeze. It will drop like a rock.Another reviewer says they're loud. FALSE. I modified mine with an air stone to make the bubbles smaller, hooked it up to a Tetra Whisper pump rated for a 40 gallon tank, and it's practically silent--infinitely quieter than the hang-on filter it replaced.Yet another reviewer complained about the lack of directions. Well, that's a problem only if you're living in the year 1994. YouTube is your friend. Within about five minutes you'll know everything about sponge filter installation, including how to do the air stone mod.Some legitimate drawbacks? Minus the air stone modification, I feel the the bubbles are too big and the system is noticeably louder. For the manufacturer to suggest that an air stone is not needed is like a mechanic telling you your car doesn't need a muffler. Secondly, this is a big, beefy filter. If you're into an aquarium looking as natural as possible, a giant black sponge in the corner isn't the most aesthetically pleasing of tank decors. And lastly, if your light source is close to the surface of the water, the mineral deposits from the bubbles will build up pretty fast on your light cover.

I woke up one morning to find a lot of koi eggs in our pond. The koi were already eating the eggs, so we gathered as many as possible and made a “fry tank” using a large plastic bin and air stones. Days later we had hundreds of small fry. I needed a filter for the tank, one that would not suck the tiny fry into. purchased one sponge filter and found that it worked very well for my intended purpose. The filter didn’t pull fry into the sponge. In fact, the fry liked to eat off of the sponge. I soon ordered the cost-saving 4-pack to spread the fry out into additional tanks. The filters are easy to clean. As other reviewers have stated, the filters are large. I recommend this filter if you need an economical filter for a tank that does not have a heavy load of debris in the water.

sponge filters are great, and these are high quality and inexpensiveUpdate 01/2021: I've changed my mind on these filters. They are inexpensive and they work, but there are better options out there. I find the sponges are too fine pored and require cleaning too frequently. After a few months of use, the air-exit holes in the base of the stand also clog up with calcium deposits and I ended up cutting out plastic air tube contained in the lift tube. Some of the sponges are also starting to disintegrate after a few years of use. The bubbles produced are too coarse (meaning they are loud and inefficient) as well and you can't add an airstone without modification.I'd much rather have a coarser sponge and the ability to add airstones without modifications.

Did the job for my 10 gallon aquarium, where i only have a Betta fish. However, 2 of them wouldn't handle my 20 gallon aquarium with 6 corydoras and 10 neon tetras (all of them young and small). I decided to order sponge filters from another supplier, and to my surprise, their 20 gallon sponge filters were about 50% bigger than these ones.Also, you would have to make some modifications if you want to add a bubble stone(barely fits even after modifications)I would recommend this product for an under stocked 10 gallon tank .

Less than two weeks and I've already gone through 2 of them. They start out just like the other ones I have, they sink. But after a couple days these became buoyant! I don't know how. The other ones I have never did that before. I'm assuming that they have the wrong density of foam. They do seem more porous to me, but that may not have anything to do with it. But they do float!