Review on Top Fin Element Filter Cartridge by Carrie Tunks

I bought these filters for my son's beta aquarium which are made up of the same brand top fin. First, all of these filters seem hard to find. I can't find them at local pet stores at all. That's how I ended up here. I changed the water, changed the filters, and on the 4th day the water became uncomfortable, started to get cloudy. On the 7th day the water was green. I decided to clean and process these filters, discard them and use 2 more filters. Remember I bought 12 packs of filters so 4 are used in a 2 week period. I'm currently using 2 more because they don't work. The pet store recommended changing tanks and brands because they had also heard negative reviews. I will not buy again.