AQQA Aquarium Fluidized Moving Bed Filter,Media Submersible Sponge Filter with Air Stone Ultra-Silence Dissolved Oxygen,Air Pump Accessories,for Fresh Water and Salt-Water (L 15-55 Gallon)

Amazing natural filter. As a fish hobbiest I don’t usually have faith in a filter this inexpensive but this is my new holy grail of freshwater fish keeping. It does take a day or two before the media starts tumbling but once it’s soaked it does eventually tumble. I honestly can’t understand why someone wouldn’t love this.

Took a couple of days before the beads started mixing like in the video . I honestly thought they weren’t going to stop floating at the top and decided to leave it be for the time until I could figure out something . Came home and maybe the 3rd day after being submerged and they finally aren’t just floating to the top .

It took a few days in the tank for all the filter media to move, but now it seems to all be swirling. Time will tell how well it filters. Not a fan of how loud the bubbles are but I just moved it up so the part that bubbles is above the water.

The media could not be loaded. Ordered two of these for an over stocked 70g to replace a pair of sponge filters and accompanying two Fluval 407s, both set up as straight biological. Due to the fact I’m over stocked, heavy filtration, namely biological is necessary. I use no chemicals and haven’t for the 15 years these guys have been with me.One thing I need to say, I’ve seen the review videos on here where people aren’t using a big enough air pump. That K1 media needs to be tumbling, I mean, it is by design after all.Also, I replaced the fine foam that it came with plastic pot scrubbers which excels at growing bacteria. If you don’t have them, just take the foam at the bottom that it comes with out. That foam is too tight and acts as a mechanical filter which will require cleaning. DO NOT CLEAN THIS FILTER. Use it as a Biofilter. It will take about 4 weeks to establish, but make sure you have plenty of flow through it so it’ll be effective.The purpose of the this filter media is not to filter out particles from the water as is often assumed. The media serves as the habitat for a vast array of microorganisms that include bacteria, archaea, worms, ciliates, flagellates, and many others. These microorganisms live in a community that is based on biofilms. The biofilms are created by bacteria that secrete extracellular polymeric substance (EPS), which is often called “slime”. The community forms a bioreactor that processes the waste and turns it into food and energy for its members, and ultimately into organic or inorganic products that are then used by plants, evaporate, or removed by water changes. It takes a considerable amount of time to establish this “filter community”; consequently, it is very important not to disturb it unless absolutely necessary.

Folks, if you’re going to buy these, understand what they really are. They ARE NOT SUITABLE AS THE SOLE SOURCE OF FILTRATION! These are fluidized bed media reactors that happen to have a piece of foam in the bottom. Yes, the foam will filter water UNTIL IT CLOGS UP! What these are good for is tumbling media that do one of two things. Provide a home for bacteria, or provide a home/food source for bacteria. First thing to do is yank that foam out. Throw it away. If you want to provide a home for bacteria, use the media that comes with it. What I use them for is to tumble DrTim's Aquatics NP-Active Pearls. This product provides food and a home for beneficial bacteria. Here’s the scoop:“ NP-Active Pearls are an easy alternative to carbon dosing, suitable for all water types, fish, and corals. 100% natural polymer pearls grow beneficial bacteria & remove nitrate and phosphate from water. Naturally the carbon pearls clean messy fish tank algae. Keeps your aquarium balanced. Pearls should be placed in a fluidized reactor or similar device where pearls are kept in constant motion with sufficient water flow.”I have 6 aquariums. A 90 gallon reef tank, a 33 long saltwater for my moray eel, and a 55 gallon salt water fish only. On the freshwater side, a 55 gallon with Tiger Oscars, a 20 gallon tetra tank, and a 10 gallon planted shrimp tank. Every one of them but the 90 gallon have two things, one of these reactors with Dr. Tim’s pearls, and an algae scrubber. All the saltwater tanks have custom sumps with a custom algae scrubber built in. The freshwater tanks have HOB algae scrubbers I custom build using Marina filters.I’ve been an advanced aquarist for over 55 years, have a BS in Marine Biology and a MS in Mechanical Engineering. I can’t tell you how many cars I could have bought for the money I’ve spent over the years on stuff that just doesn’t perform, so I either design/build from scratch or design/modify OTS hardware. I never have water quality problems, and if I lose a fish, it’s due to old age.

The reviews were great but I'm not sure why. It's certainly cool looking to watch the filtered media move around but it's not very useful, except if you want to put other media in there, such a purigen, charcoal, etc. instead of the floating plastic. In fact, over time, some of them got little spots of brown algae on them, which rendered the experiment basically worthless.A couple of things to know. The top will be very noisy when air goes through. others suggested drilling more holes in the top - which definitely worked. A must do to keep it quiet.Removing the filter on the bottom to wash is a major PITA. You have to try to unscrew the bottom cap, which can be very difficult. The top half can also be a challenge. I'm not sure what this does other than move some media around that might contain beneficial bacteria, but doesn't seem near as porus as the standard blocks. Perhaps there is some science to this of which I'm unaware but it didn't do very much.This would be easier to remove with a magnet than the four suction cups, but it is what it is. At least it's not as difficult as others. I do have to remove it to clean it off every month from algae and buildup. The best reason to buy it is to put in other media and push air through the bottom. For that it is reasonably good. I'm not sure of other purposes. But it is cost effective for a solid piece of plastic. Just be aware that it's not easy to clean.