Tetra Whisper Bio-Bag Filter Cartridges For Aquariums - Unassembled, Medium, (pack of 8)

Works good. Easy to put together and cost significantly less than buying it from a pet supply store

We have two Tetra Whisper fish filters. These assemble-yourself filter cartridges or "bags" are, after assembly, the same as the ones you can buy ready to use but much, much cheaper. It is extremely easy to assemble them and everything you need is included, very nice and I think a "no brainer".NOTE: I recommend not following their assembly instructions in one respect. ("Assembly" means turning off the filter unit, removing the old, dirty cartridge to work on it, changing out the filter bag and charcoal [ditch the old, put in the new], and re-installing.) The instructions say to put the re-useable frame inside the bag first, then pour in the charcoal. I find that no matter how careful I am, some of the little charcoal particles spill out of the narrow opening or bounce off the frame as you pour and they wind up, (a.) not in the filter so less service life, and, (b.) on the floor or counter to be cleaned up. Instead, I recommend pouring the charcoal into the bag first with the bag "mouth" wide open and unobstructed, much easier and less mess and waste, then insert the frame into the bag. The only caveat is that with the charcoal in a pile at the bottom of the bag, the frame may not go down in all the way, so have to shake or flick the bag a bit then settle the frame in deeper once or twice, much as you might flick a single-serve paper bag of sugar to move sugar out of the way before tearing off the top.I haven't "autopsied" a factory-assembled bag vs one of these to confirm that they aren't cheating by putting in less charcoal, the price difference is so great that it's surprising, but they seem to work for as long as the factor-assembled ones. The box says "Made in U.S.A." so I hope we're not putting someone out of work by taking away their factory assembly job, but I'm sure the factory-assemble versions remain a major part of the market. We keep a few factory-assembled ones around for when we are away and the pet sitter may have to change cartridges, not they couldn't use these (not rocket science!) but we try to make it easier for them. For us, we use only these unassembled ones.The Whisper filters seem effective and are quiet. They do build up some crud over time and should be rinsed out once in a while, including taking off the bottom section (intake screen and pump), but other than that they seem good. Of course, the local pet store fish experts, who do seem to know their stuff, say that sometimes cleaning is good and eliminates crud that otherwise makes the water cloudy and the fish prone to infection, while other times cleaning removes "good" slime and organic material that are necessary to support or are part of the "good" bacteria that should be present in an aquarium to digest and remove ammonia and nitrates (i.e., piss-eating bacteria), since not having them results in impurity build-up in the water than can irritate, hurt, or ultimately kills the fish. But no one has been able to tell me how to tell good slime or crud from bad slime and crud beyond saying that if the tank water looks clear, don't sweat the slime, but if cloudy, that's bad. They also say to add "biological" treatments or additives when appropriate to establish or restore lost good bacteria, but then add that the "good" bacteria under some conditions can also make water cloudy and bad. Confused yet? So am I. At this point, I should say that I like hamsters and cats and dogs myself, but we have the fish for the kids (sigh) and we do the best we can. So if you have fish and this type of water filter, I would recommend these unassembled ones, they are sooo much less expensive than factory assembled, easy and very little trouble to assemble yourself, so you can save money and/or change filters cartridges more often. It's all good.

Size: Large 12 PackFirst: People want to know what the actual size of these are so they can decide if they'll fit their filter. I got these to use with a Tetra Whisper 30-60 that I got at WalMart. They're exactly the right size for this filter (and certain others, of course).Measuring the bags or the frame over which you place the bags gives, of course different dimensions. But here's what I get measuring a brand new bag stretched over the frame at the very outside edges of the bag: The frame and bags are tapered so that they're narrower at the bottom and get wider towards the top. That allows them to be inserted into the filter more easily yet still fit in tight enough to make it hard for the water to short circuit around the bag.At the top, measuring to the very outermost reaches of an unused bag, I get a width of almost exactly 5". At the bottom, where it's narrower, measuring the very outermost edges of an unused bag, I get a little under 4 3/4". The height, again, measuring from the very bottom of the edge of the bag to the top of the frame (which sticks out above the top of the bag, of course), I get a height of just about exactly 7".Naturally, the bag's edges get smashed inward a bit, its edges curling up and mooshing in as you slide it down into the slot for it in the filter. So measuring a used, wet, bag will give you slightly smaller dimensions. It might actually be of more use to people to know the dimensions of the frame since that's what has to match and fit exactly into your filter, and you can measure your existing bag frame to see if it'll be the same.The frame I got with these "Large" bags is about 6 3/8" tall, 4 5/8" wide at the very top, and about 4 1/4" wide at the bottom. I'd compare those dimensions with the existing frame from one of your filter bag assemblies to decide if these "Large" bags will fit your particular filter.I cannot comment on the sizes of the medium or extra large bags. Again, the ones I got are the "Large" size.-------------------------------Now for the review:Based on use with my Tetra Whisper 30-60, these work just the same as the pre-assembled units, but cost a lot less. Once assembled, they're exactly the same as what come with the filter.The amount of activated carbon supplied for each bag in these kits is the same as the amount that comes in the pre-assembled elements. I personally don't think it's enough, so I like to add more (about three times as much as what is supplied) when I make up or clean mine. That means obtaining similar granular activated carbon elsewhere, of course.-------------------------------A bit of advice for people new to all of this:One thing that's important to keep in mind with any aquarium filter is that along with mechanical filtration (to get out obvious debris) and chemical filtration (the activated carbon), the main function of most aquarium filters is the biological filtration provided by the so-called "beneficial bacteria" which hopefully colonize your filter elements.The basic idea of this biofiltration is that two types of bacteria will eventually colonize the surfaces in your aquarium and especially your filter media. One type of bacteria "eats" the ammonia excreted by your fish, and, as their waste product, excrete nitrite. The second type of bacteria "eats" nitrite, and, as their waste product, excrete nitrate.Ammonia is highly toxic to fish even at fairly low concentrations (depending on pH to a great degree). Nitrite is also quite toxic to fish. Nitrate (the end result of all of this bacterial action) can be harmful to fish at high enough concentrations, but is not nearly as bad as the ammonia (produced by the fish) and the nitrite (produced by the first type of bacteria mentioned).So once your aquarium and filter system have established colonies of beneficial bacteria large enough to metabolize the amount of ammonia produced by your fish, the main things that harm fish in a closed system (like an aquarium) will be kept in control. However, the nitrates will still build up over time, and this is why we need to do periodic water changes on our aquariums. People do water changes every week or two, generally.But without sufficient bacterial colonies, the ammonia produced by the fish would kill them in very short order. You'd need to do almost constant water changes to keep the fish healthy.So the main point I want to make is this:If you remove and replace, or clean too thoroughly, your filter media, then you will be discarding much of your beneficial bacteria. This can kill your fish. To learn more about this, read up about the "Nitrogen Cycle" for an aquarium.So with a filter like the Whisper 30-60 that has two identical sets of filter elements, I prefer to avoid replacing the filter bags until they're absolutely falling apart. Instead, I rinse them out in used aquarium water and replace the activated carbon when doing a water change. This preserves the bacteria colonies in them and avoids shocking the tank by removing too much of its beneficial bacteria all at once, destroying the balance.Remember: You need to have enough bacteria present to handle the amount of ammonia produced by your fish (and rotting food from overfeeding), etc. Over time, the bacteria colonies grow to match the amount of ammonia being produce by your fish and your excess feeding. But there isn't a lot of excess bacteria because if there were, some of them would starve off due to a lack of ammonia. So the bacteria tends to stay in balance with your fish "load".If you suddenly remove a large percentage of the bacteria present in the tank and filter(s), then, until the bacteria can reproduce and the colonies grow back, there will likely be an excess of ammonia, and this can kill or injure your fish quite rapidly. So you want to protect your bacteria so it can protect your fish.I never do much of anything to the open-cell foam elements. They're meant to house a lot of beneficial bacteria, and cleaning them off will just remove that needed bacterial slime (biofilm). You don't want them to plug off, of course, but if you've maintained the bag filters ahead of them, then nothing should reach these foam elements to clog them up, anyhow. If they do plug, though, then I recommend rinsing them gently in used aquarium water, and not trying to get them too clean. Remember: You WANT that slime of biofilm to remain since that's your necessary bacteria colonies! The thin slime layer is good. :)When I do need to actually replace one of the filter bags, I only do one side of the filter at a time, waiting a month or more before replacing the other side. That way, hopefully the first bag that was replaced will have built up enough of a bacteria colony to handle a lot of the load before I dispose of the other one.Some of these filters are smaller and only have one bag and one foam element. In that case, you want to be especially careful not to clean the foam element if possible. And ideally, don't replace the filter bag any more often than you have to. Again, just rinse it out in used aquarium water to restore good flow, and replace the activated carbon when you're doing a cleaning.When you DO have to replace the filter bag (they last about a year for me) you may want to rinse what's left of the old bag, and then put it into your filter right behind the fresh new one. Then leave it in there for a month or so to provide its bacterial help while the new bag gets seeded from it (the old one), and finally establishes its own new colonies of bacteria.I like to have several filters in each tank. That provides a "backup" location for bacterial colonies to help handle the load when you do have to clean or replace a filter or have a failure of some type.There are some great on-line forums for fish keeping where you can ask questions and learn more about all of this.

Easy to assemble, so save your money. Cheaper than the ones already assembled.

Easy and important to replace about once a month. Far better price and quantity than getting locally.

Great product, much cheaper than assembled ones.

These keep my water very clear even when a grandchild accidentally dumps a bunch of fish food. It captures and traps the excess food and I just change it out a few hours later. I’ve ordered these for over a year

When choosing a brand of pump/filter, this is the least expensive filter I have found so I buy pumps that use this filter.

Good price compared to pet shop

What a money saver… I have been using these for years and also it save on the package waste as there come in one box!

Los filtros cumplen su función y están a muy buen precio. A diferencia de otras marcas que los venden ya listos para usar estos se deben armar pero en lo absoluto es algo complicado. Además, como se debe reciclar el plástico que les da estructura, son más ecológicos también, eso me gustó.

Quick shipping. Exactly what I needed and for a great price! Thanks

Fantastic so easy to finish putting together and work so wonderfully in my tropical aquarium