FluvalFlex Foam Filter Block, Replacement Aquarium Filter Media, A1375

Worked very well for my 5 gallon shrimp tank

We decided to do a deep clean four days ago on our saltwater tank. After the clean it did not return to its previous state of crystal clear water and appeared very cloudy with white particles. We assumed that we had kicked up some funk in the sand and created a bacteria bloom. This was the first time we have encountered this, so we did our research and decided we needed to over oxygenate the water, and then add fine filtration to the system.When this first started we did a water change, and added a fresh zorb pack to help clear the tank. That with increased aeration seemed to help but was not making quick enough progress to settle our nerves. After four days of waiting for the cloudy water to clear, we decided to add these active carbon filters to the mix! After a good rinse we added these to the filter and OVER NIGHT they seemed to have completely cleared up the tank!It was a relief to wake up to clear water and happy fish! Overall the cure to the bacteria bloom seemed to be these active carbon filters, and water aeration (we added a new bubbler)! These are an affordable option that did the trick and arrived as expected! They are small, but I just used two in my filter to create full coverage. We will keep these on hand and incorporate these into our tank maintenance moving forward for crystal clear water!

They do what they say. What more do you want?

Just simple carbon works as intended

The media could not be loaded.  I have a Fluval 10 gallon tank with two Gubbies; before using this nitrate filter, I struggled with yellow and dirty water that needed to be changed weekly. Now, using a Nitrate filter, the water stays clear and clean for more prolonged periods.

They took all the nitrite out of my tank...It took about 24 hours ..Bit I had an almost zero reading.After many water changes of many months.these things are legit@@@

These are cheap and easy to use. Just rinse in the sink and swap out with the old one. Cheap enough to change frequently and keep your aquarium clear and odor free.

A must for your aquarium I have been using this brand and it helps keep the smell down and removes harmful chemicals

Fits all my fluval media but there are cheaper options

Exactly what I wanted.

Helps keep tank fresh

Filtro para pecera fluval flex queda perfecto

Works perfectly in my Fluval Flex 15 gallon tank. I wanted to replace my old filter block as I think it had become clogged up. This replaced it perfectly: it was an exact fit.