Active Sponge Filter

Filter - Active Sponge Filter

Regular price $10.95
Shipping calculated at checkout.

You should choose a carrier that can get these to you within 2-3 days transit time, Priority Mail is a very unreliable choice when selecting the shipping method. Please do NOT order so it travels over a weekend.

NOTE: If you test your water after adding the filter and have no ammonia and no nitrites, then everything is good. You do NOT need to see nitrates to know it's working. 

Made from our Pro-Level Reticulated Foam, specifically suited for colonizing nitrifying bacteria at the highest levels in aquariums.

Size: Actual filter size varies with each filter.

  • Large - range from about 50-100 cu/in.
  • Small - ranges from about 30-60 cu/in.  

We cannot tell you how many you need for your tank. Tank size does not determine how much filtration you need. Bio-load is the determining factor and it's a complex formula. In general, you have to use your experience to know how much filter material volume your situation needs. If you are inexperienced and must guess, then go with 1 filter per 20 gallons, knowing that it may be over or under filtered. If you are going to use the active filter solely to establish an existing filter, then one or two max, would be enough for almost any size tank.

If you are putting the filter in with new-born fry or a tank that is 5 gallons or less, then the 50ppi (pores per inch) is the best choice, otherwise, the 15/30ppi filters are a better deal for a much larger size. The Large can be either 15ppi Blue or 30ppi Black - our choice. We send what is ready. The Small are 50ppi Charcoal. 

It comes with a lift-tube. You must supply the airline.

We ship when you order, so it's your responsibility to avoid weekend and holiday delays. You should try to make sure the carrier you choose will get them from our location (14760) to yours, within 2-3 days. They will survive longer, but it will also take longer for the bacteria to build back up to the levels needed for your tank.  Orders that arrive after 8 AM est, will not ship until the following business day.

When you receive these, make sure to add any water in the bag to the tank. Do not worry about it being dirty. It is full of nitrifying bacteria and you do not want to throw this out or siphon it out with a water change until the aquarium is fully established.

Filter Setup

When receiving the filter: Be sure to add the dirty water in the bag to the tank with the filter. It contains valuable nitrifying bacteria. 

Setting Up Filter: Run an airline to the lift tube. Insert the airline into the hole in the top side of the lift tube and thread it to within 1/2" of the bottom. Then insert the bottom of the lift tube into the hole in the sponge. You can put the filter into any part of the aquarium. If it floats, gently squeeze the air out of it.

Some people cut these to fit inside of power filters. That will work if the fit is tight, but if water can travel around the filter instead of through it, then that is what the water will do and it will not be as effective in establishing your aquarium.

We are not fans of "fish-less" cycling. It seems most times a customer is having trouble cycling their aquariums with our filters, it's a "fish-less" cycle. It's possible some additive in the ammonia they're adding, is interfering with their water test kit readings or is simply doing something to the nitrifying bacteria. Either way, if you add one of our active biofilters, your tank is ready for fish. Forget about adding ammonia first. Also, do not use ammonia removers when conditioning the water - only chlorine removers should be used if you have chlorine. The ammonia is essential for the bacteria in the filter to survive and grow. If the ammonia gets dangerously high (fish are struggling at the surface), then a water change is the best option.

Occasionally someone complains that their nitrates didn't go down after using this filter. It's important to know that only ammonia and nitrites are lowered by biological filters. Nitrate will actually go up, which is why water changes are still necessary no matter how good the filtration is.  

How They Work

These filters are fully "cycled", containing all the many species of nitrifying bacteria a fully established aquarium needs. Once put into a tank, the tank becomes instantly cycled. "Cycled" aquariums can still get ammonia or nitrite readings from a test kit. Cycled means you have the proper number of nitrifying bacteria species and the proper proportion of them. However, the population may not be high enough to handle all the waste produced by your animals. Assuming you have enough filtration for your bio-load, and the water conditions are good for bacteria growth, the bacteria will double in population approximately every 24 hrs in until it reaches the level where it can handle the waste in your tank. That can take anywhere from minutes to days, depending on the bio-load in your tank. Do not use ammonia neutralizers, only chlorine removers unless you have chloramines.  It's best to not do water changes for the first week unless you see the fish struggling at the surface for oxygen. If you must do a water change, we recommend this to remove chlorine.

All of our tanks contain snails, so these filter may have small snails and/or their eggs on them. The filters also have other small micro-life typically found in many aquariums.  There are paramecium and rotifers, There might even be flatworms or bristleworms. These are NOT parasites, but small aquatic animals that clean up extra food and fish waste. We never see them in our tanks and we look for signs of them often. We don't overfeed and they are most visible in tanks that are overfed.  If you don't like them, they are easily killed with formalin.  Just treat in a 5-gal bucket for a couple hours and then add the filter to the tank. The filters also contain the decomposed waste generated by the plants and animals in our tanks. They will be "dirty". This is not harmful and is what happens in biological filters. The nitrifying bacteria are short-lived and create a large amount of bio-floc as it dies off.  All of this is normal, but if you are offended by this, please do not order. Filters that are too clean, can be a reason for having a difficult time establishing a bio-filter since cleaning a filter too much harms the bacteria.

There are likely hundreds of species of nitrifying bacteria in a tank that has been "established" for over a year. This is why those commercial "starter" products with a few species, don't work very well.  Our filters contain all the species in balance and is why they work so much better.

The bacteria survive shipping quite well, but faster is better when deciding on the shipping method during checkout.  If the filter freezes, the bacteria may be killed so pay attention to the weather, here and where you are.  Try to avoid having the package sitting outside after delivery.  It can be risky to order when night-time temps are much below 0 F. We are in a potentially very cold area of the country (zip 14760).  Heat does not bother the bacteria.  In transit, the bacteria go into a dormant state and reactivates in the presence of ammonia and nitrites.  A percentage of them will survive for quite a long time out of an aquarium, so even with delays and bad weather, they persist and will often still work, though a bit slower as they recover.

The filters vary in size and shape within the range listed.  All of our Active filters are the "Internal Weight" filter version.  We have too many filter types to have them all in an "active" version and this type is easy to ship without water leaking from the bag.

These filters are "established" in our disease-free aquariums.  This assures that no pathogens are transferred to your fish.  This is safer than using a filter out of your own tanks, since few, if any are disease-free.  These filters have been running for about a month in our super healthy tanks to ensure the nitrifying bacteria are well established within the sponge.

Customer Reviews

Based on 181 reviews
Worth every penny

Cycled my tank for a few weeks before adding fish. Local big box store advised water parameters are perfect and I can add in a couple of fish that day. Added 2 goldfish and within a couple days my ammonia spiked to 3ppm an everything else was at 0. Tank struggled and fish started looking depressed and sick. Ordered this filter late Saturday night, shipped Monday, arrived to my door in California on Wednesday. By Friday my ammonia was 0, my nitrites where at .5 and my nitrates where at 10ppm. Amazing how fast it worked and best part is no more dumping chemicals trying to keep the ammonia safe and kick starting the cycle(I spent more on chemicals then this filter 🤦‍♂️).

I added an airstone which helped reduce the bubble side and noise from the filter.

Christopher Lum
it works...

I was never skeptical at all..this is no different than a buddy giving you pre-cycled media. My nitrites were 4PPM, within 8 hours, they were down to zero after placing this sponge into the aquarium.....recommended for new tank syndrome.

Its a wonder why this type of service is not common, being they want to sell those "bacteria in a bottle" products, that absolutely do not work.

Chad Jensen
Worked great for me!

Given the size of my tank and the fish inside, I was concerned about how quickly ammonia was building up after my cycle crashed. This product worked great for me! It was NOT an INSTANT-CYCLE, but it was very reassuring to see ammonia levels reducing each day, nitrites staying at ZERO, and nitrates building back up. The tank is cycled now and though I don't love the aesthetics of the cube-shaped sponge, I'm leaving it in the tank for probably a couple of months to make sure the BB can grow on everything else, including the sponge filter that I would actually like to use. I highly recommend this for speeding up a cycle and for saving the lives of your fish!

Brittany Cain
They actually work

I ordered a small filter for a 10 gallon and after 24 hours my tank is fully cycled. Been testing for the last several days and have 0 ammonia/nitrites with fish in the tank. And this was after the filter was in shipping for 3 days. Am so relieved as I’m tired of doing numerous water changes with a fish in cycle. Highly recommend and will be purchasing in the future.

Sherri S.
I'm a believer!

This will be my third order of an active sponge filter as I am getting back into the hobby after a cross country move and want to properly cycle my tanks as quickly as possible. Never used a sponge filter before now and I have to say I'm hooked! These are great for my angel babies and guppy breeders. I just like the versatility. Wish the tubes were clear and not green but that's an easy peasy fix, and is in no way a detriment. Thank you for reeling me in!!