Koller Products Replacement Filter Cartridges - Small

Thank god I found out about this product. Honestly! I had the WORST tank ever. I felt so bad for my goldfish. No matter what I tried or how much I cleaned I could not get the cloudy water clean. Also, brown slime was forming in my filter. I only found out about this because I ordered some medicine for my fish who developed a red sore on his mouth. The medicine said to clean the tank with this after the five-day treatment. I have a Fluval Filter but I bought this anyway and stuck it in with my charcoal bag. I could not believe the difference after only 24 hours! It was so clear. And it has stayed clear ( it's been probably two weeks at least!) I don't know what's in these--but I am sooo happy and I'm sure my poor fish are too! Thank you!

Needs to be replaced often or else it doesnt work in tge filter but it came with alot and great price

Filter cartridges work well and shipped fast. These are used for filtering the tank of goldfish my grandkids won at the county fair. I originally bought them because of price I keep buying them because they work

I used these for a 10 gallon tank with 2 goldfish. I had to replace filters almost every 2 days. These might be good for a beta fish, filters woild probably last longer.

I'm so glad I found this product, Pet Land closed down and Petco doesn't carry this filter. Works great with my fish tank. Ships fast.

These really work well. They keep the tank water crystal clear! Just follow the package directions!

Like them works really well

Great price. Work great in my tank. No issues.