I purchased the small size twice. It's a good size, doesn't take up much room. The first one failed after a year of use, but was my fault, as I left it running during a power outage. It couldn't suck water up when the power came back on, and overheated. (You need to pour water into it to start it filtering.) The second one I had (which also lasted a year.) needed to be cleaned, so I shut it off to clean it, I plugged it in and it didn't run again. Flow is pretty good. Worth it if you're fine with spending 15 bucks a year (not including cartridges.) I would get an internal filter if you live in an area with a lot of power outages.

Set up working fine. Come back to check 1 hour later, not running. Will not start.DO NOT BUY

This filter is great for any 5 gallon tank and below, this could even work for a 10 gallon possibly, but I’m not sure if it would be as effective since it is very small. Take it from me that I’ve had a lot of hang on the back filters and a lot are noisy and compared to most this filter is quiet. It has a very slight humming noise but like i said others are so much more noisier.A lot of people say their HOBs leak in general and most will leak if you don’t replace the filter cartridges in time, they get dirty fast and then the water level raises in the filter making it come out of the back and leak all over. This filter like other won’t leak as long as you replace the filter cartridge and since this one has a small cartridge you have to replace it more often than others.Overall I really like this filter it has a sleek look to it and is very effective. The back of the filter has some space for customization so I like to put filter media or carbon in mine and it fits nicely. After I ran out of the cartridge that came with this filter I hadn’t orders them in time so I used a cartridge for a different brand filter and just put It in there and it works so you can really do a lot with this filter. Another pro tip, you can buy filter floss in bulk for really cheap and then aquatic carbon for cheap so you don’t have to keep rebuying the filter cartridges.

Don't bother with the foam or carbon insert included. I also replaced the small foam tip on the intake with just regular filter foam cut to size. Used fluval filter foam inside as well, small square cut to fit, used ammonia diamond carbon mix in a reusable bag, fluval ceramic rings on top. It works amazingly well. I got this for a small 2.5 gallon and I had to modify it slightly to lower the flow. I would say its perfect for a 5 gallon, and would maybe manage a low bioload 10 gallon. I wouldn't really say its great for smaller than 5 gallon. I had to modify it, add extra media, use a diffusing tray and change the hard scape so that the waterfall flow is hitting the mopani wood and not just flowing freely. After that I've gotten it to a super calm but strong flow.I bought this knowing full well that I would be making the internal media and likely modify it. Do not buy this thinking the stuff provided will work, trust me it won't. The flow is insane too with their media. But I would say its well worth the money. I was using the topfin betta filter and honestly as far as small internal filters go that one is great, but this filter once equipped with proper media is blowing that betta filter out of the water, they are relatively the same price except with the topfin filter I had a really difficult time using my own media and I didn't like that with the top fin filter its essentially just swishing water over a carbon filter...Has a light hum. Its super tiny and cute, insanely strong! Like, almost too strong? Definitely use foam in the first chamber to slow the flow a little. Oh. And no clog indicator! So be mindful to check that the water level is where it should be to avoid overspill.Overall. Better than any filter I have bought so far under 15 dollars. I highly recommend it. Its got as much power as some of the 30 or 40 dollar filters I've bought, those just come with media packs. Plus bigger and clunkier. I like how tiny this one is.

I have a 75 gallon tank, a 10 gallon tank, a 5.5 gallon tank, and a tiny tank (about 1.5 gallon capacity). I keep African cichlids. I have kept cichlids for 25 years. I've kept only males for many years but recently introduced a couple of fish that were females... and suddenly I have a fish nursery on my hands.The pregnant female is kept in a flower vase with a sieve lid inside the main tank, so she can enjoy the usual filtration (and the lovely view) without getting chased and pestered by the males while she is holding fertilized eggs. (She doesn't eat while pregnant; she is a mouth-brooder).When a female releases the fry (babies), I transfer the babies into a smaller tank. Once grown, they will be sold at a pet shop. I have two female electric yellow cichlids that keep breeding with the males, hence my need for a few fry tanks, though I am now keeping both females in the largest fry tank with the largest fry (too big for them to eat) to give the females (and me) a break from back-to-back pregnancies.My 5.5 gallon and 10 gallon tanks have Tetra brand 5-10 gallon "whisper quiet" filters which have been outstanding and powerful in cleaning water even with 12-30 fry eating and pooping. I highly recommend the Tetra filters. You cannot hear them at all, either; they truly are "whisper quiet".But this Boxtech filter I absolutely CANNOT recommend to anyone who cares about their fish. It is inefficient -- it does not powerfully clean/filter the water as advertised. There is no malfunction in the filter itself, I can see it works as intended, but it is dismally inefficient.Every week I am doing partial water changes on the juvenile tanks, and carefully monitoring all other variables (temp, pH, etc). The Boxtech filter is hanging on the smallest tank -- a capacity that should absolutely be managed by a filter that is advertised to handle much greater water volume (3-10 gallons). And yet I notice that it is the tank with Boxtech filter that is the filthiest.The inefficiency of this filter has caused stunted growth and fish fatalities in my fry, whereas those babies that have been in other tanks using Tetra filters that supposedly handle the same water capacity as Boxtech's filter have crystal clear water and are thriving. BOTTOM LINE: IT DOES NOT CLEAN THE WATER.Aside from this, it is fussy and flimsy; the little sponge piece at the bottom of the tube falls off constantly (we put a rubber band at the base of the tubing to prevent it from constantly sliding off). The size of the filter cartridge alone should tell you everything you need to know. Boxtech's 5-10 gallon filter cartridge is approx 1 1/4" by 3 1/4", (about the size of a movie ticket -- remember those??), whereas Tetra's whisper quiet 5-10 gallon filter cartridge is approx 3" x 5 1/2". Additionally, the intake and outflow of the Tetra is much more powerful, like a silent little waterfall of crystal clear goodness.Considering I was using this Boxtech filter on the smallest tank (since the Tetra filter was too large for the side of the tank), with smaller water filtration requirements than what Boxtech boasts it can handle, and since the fish in the water with the Boxtech were tiny fry rather than larger juvenile or adult fish (with bigger food and poop clean-up needs), Boxtech's filter has no excuses. Lost all but 3 fry from our youngest batch due to the inefficiency of this filter system, and I am about 10 days past the "return by" date for refund eligibility, and there does not seem to be a way to contact the seller, so I wanted to get on here and warn other hobbyists or fish owners.Go with Tetra 5-10 gallon filter if your tank will accommodate it; it is even less expensive than Boxtech's filter. If you have very tiny fish (such as my youngest fry which were about 1/4" long), just tie a bit of cheesecloth around the bottom where the filter slits are for intake, to avoid anyone getting sucked in. Once they were just a little bigger, the cheesecloth can be safely removed. Please avoid Boxtech's filter at all costs. It has already cost me many baby fish and $14. A real shame.

The product seems to be working fine, but the build quality is poor. One of the tube fittings had a crack in it.Cheap plastic material. However I'm not disappointed with the product overall, it's good for a 10 gallon aquarium.

. And the unit became so hot almost burn my fingers. Luckily we found out before it cause any fire harness to my house. Be aware!!

Fits my filter