Penn-Plax Cascade 170 Fully Submersible Internal Filter – Provides Physical and Biological Filtration for Freshwater Aquariums, Nano Tanks, Turtle Tanks, and Terrariums

It's cheap and small, so I wasn't expecting much for my 2 gallon setup, but I think it'll do great! I've got it in a little .5 gallon tank for now, just to cycle through with my plants and moss balls, until I get it all set up tomorrow. But it's doing fantastic so far, keeping the water crystal clear. I plan on including some charcoal soon, just to give it an extra boost, and maybe slow it down a little, because it's got a very strong flow, even on the lowest setting. But I'm not complaining, I can always add more media to slow it down. I'm very impressed, and excited to get it all set up!!

I had originally purchased this for a nano tank and was impressed with how much water it was able to move. It was able to clear up my tank very quickly, and was fairly quiet overall. The filter has a small venturi port at the top and comes with an attachment to extend the port opening to be above the water line. Taking the filter apart to change out the sponge was easy and it has an adjustable flow lever on the side of the unit that allows you to adjust the flow to your needs.Although the filter was very impressive for the price and size, it does not come without its negatives.1) Though not necessarily a negative as this is relative to the size of your tank, the filter is powerful - much too powerful for my smaller nano tank that was 2.5 gallons, even on the lowest flow setting! I would recommend this filter for tanks of 4-10 gallons or long tanks where the flow has more distance to disperse.2) The suction cups on the unit are very weak. I found myself having to stick the filter on the glass again ever 3-4 days as it would constantly lose suction to the glass.3) The venturi port, though nice, was inconsistent for me. As you get obstructions in the outflow, the venturi effect eventually stopped and instead of drawing air in, it started to spit water out the top. You have to be careful with the placement of the air hose in this case as to make sure that if this does happen, the water will not spray out onto your floors. I opted instead to just not use the port for air and added an airstone instead.Overall, I think this Penn-Plax filter is great for the price. It has a very powerful pump that moves plenty of water, and effectively filters the water. There are issues with things like the suction cup mount constantly losing suction to the glass or the venturi air tube having the opposite effect and spraying water out instead of intaking air. If you don't mind just having the filter hang by the power cord or opt not to use the venturi air tube, these aren't really issues. Just make sure to have a large enough tank to contain all that power!

I won't lie, this filter is far from top of the line, and doesn't do much in terms of actual filtration power. What it does well is create a nice current in a compact design, which was exactly what I was looking for for my planted riparium 10 gallon aquarium, with a nice compartment for a modest amount of biological, physical, or chemical filtration media. If you have a very small tank with a very low bioload and are just looking for something to create a nice current without taking up a quarter of your nano tank, this is the thing for you. I've had mine for two years and it's taken a serious beating since then, and it still works just fine even after things like mike eheim canister filter have degraded and malfunctioned. If you need high amounts of filtration, buy a canister filter or a good HOB, otherwise this is a great choice for very small aquariums with low bioload in need of flow or moderate chemical/physical filtration. I mostly use it as a powerhead with a little carbon or ceramic media depending on what I want, which it does very well.

It was great while it worked. It died in just over a month, whereas the previous filter worked for about 8 years. Buy something else.

I am impressed!!. I bought this to replace a filter I had on a Walmart 19.99 1.5 gal acrylic tank. The one I had kept spraying water out the back near my plugs and it had to go. This was what I was hoping a cheap fix, however I had my doubts. For a little cheap filter it is amazing. I left it in the small tank for a month. I have a tetra and 2 snails in my tank and already concerned about the bio-load. I did a few water changes using a turkey baster but did not touch the filter. It continuously kept a strong flow and now after a month I figured it is time to pull the filter and clean it out. Not bad at all which tells me I probably can push it a little more as far as occupants in my tank. Do not underestimate this little pump, it is a beast for its size. I only have one complaint. Trying to snap this thing back together after you clean it can be a challenge. I have no patients and was afraid I was going to break it. Other than that I would definitely recommend this filter for a small tank.

Got this to add a bit of flow to the end of my 20gal long. The low flow and the directional output were exactly what I was looking for and it worked great, for one night. The suction cups are tiny and weren't strong enough to keep the pump stuck to the glass. I would clean the glass and reseat it in the morning and by the evening it would come loose, which makes the whole filter basically unusable.