Penn-Plax Small World Replacement Aquarium Filter Media (2 Pack) – Safe for Freshwater and Saltwater Setups, SWF1C

Despite knowing these are amazing filters, something in my head still tells me that a more expensive or electric filter is better. For a tank on the smaller side there really isn't a better choice. Ideal for my bettas. Doesn't hinder their swimming in any way, but keeps the water healthy and clean. I use one cartridge for 4-6 weeks, rinsing any solid debris in the water taken from their tanks in a weekly water change. Rinsing the dust and saturating the sponge of a new cartridge in the old water from a cleaning. The casing is surprisingly more durable than it looks, I know because occasionally I take the sponge from a used cartridge out to cycle a new tank and it takes some work. I really can't speak highly enough of these filters

Filter water

I have a number of aquariums and tanks in my house. Most have heavy duty filters. I bought a little betta and I felt his tank needed a filter. Bought one at the store and bought the cartridges here. Came very quickly---- in about 5 days. PROS: Easy to set up, cheap, keeps tank very clean, has a bubbler CONS: Gets dirty very easily, Has to be replaced every week (the purchase only lasts 2 weeks), and cannot be cleaned out Overall, I would suggest, but only if the tank is very small.

Good product, good price

This is an absolute must if you are using an air pump to filter your small tank. The cartridge have bio media/carbon and a sponge, and these are essential components for keeping "good bacteria" in your tank, besides being able to filter and oxygenate the water. Personally, I do not replace the cartridges often. What I have done is cut the base of the cartridge so I can take the sponge out and rinse it (make sure you do this in a little container with aquarium water). Then I put it back in the cartridge. That way I can keep the sponge clean and the bacteria that allows the tank to be cycled (and save money). Alternatively, cutting the bottom will give you the opportunity to upgrade the media and sponge of your choice (see picture). I would suggest using an adjustable valve to control the air going into the filter, so you can increase or decrease the amount of bubbles (the filter is a bit noisy, but is just the nature of any box filter design). I've had great experience and results with this product in my 5.5 gallon Betta tank.

I really like these little filters. They are a good deal and very easy to change out when dirty. I have a small 6 gallon planted tank with some little critters and this filter does the trick.

I’ve used these before and am very satisfied with their durability and ease of use.

I purchased a betta fish for my son and a small tank. I soon realized the tank needed a filtration system, even though the tank directions said it did not. The filters work great in trapping debris and filtering the water. Bubbles is very happy.

Perfect replacement cartridges for my little Small World filter which I'm using in a 12ltr tank reserved for baby Platies! 🐟 Unfortunately these cartridges don't come apart, so you can't prolong the life of them by rinsing the interior sponges out in tank water, making them pretty expensive seeing as they need changing every 2/3 weeks, but at least they come in a two-pack so there's a spare for the next change-over. Easy to click in and genuine Small World filter media 🙂

Gr8 4 small tanks

If you do not have a adjustable check valve the pressure from these filters will be very strong but the filter does it’s job well with regular siphoning, without siphoning filter gets dirty very quick and will have to change the cartridge before 4-6 weeks as it specifies.

These are great and very easy to use, it works out cheaper than buying them individually. If you're new to this, these are just the replacement filter cartridges and you need to also buy the Small World pump to use with it. I usually need to change the filter every two weeks.

Easy to use, read and replace