🐠 Penn-Plax Filt-a-Carb Replacement Activated Carbon Cartridges (2 Pack) - Enhancing Chemical Filtration in Freshwater and Saltwater Aquariums Review

Doesn't fit my new gravel system. The original system is a tube that runs all the way through the filter head and ends with an air stone at the bottom of the tube. These filter heads are too narrow and you need to modify the hose with a soft air hose, making the heads unadjustable. Instead, you should buy cartridges that fit into the front of the filter head.

These Penn-Plax Filt-A-Carb are the best for my in-ground filtration system. They last a very long time. I especially like how the air bubbles move through the water surface. They had a lot of air in the water, which is very good for the fish. I think it looks better than other filters, especially in a 10 gallon tank. I would recommend these little carbon filters to anyone who has an underground filtration system or is thinking of upgrading to one.

I have an undergravel filter with two hoses going up the back of the tank. Tubing tips are cartridges designed to eliminate excess CO2 in the water. Cartridges need to be changed every two weeks and are the cheapest you can find at Revain (although it might be cheaper to find them at your local pet store). They work well and I love the gravel pack setup. I would recommend it to anyone who wants the same setup.

These cartridges are the perfect size for our gravel pack. These cartridges are not breathable. Our filter system is cleaned regularly and works perfectly without cartridges. We have had other cartridges without this problem. They're just kind of cushioned so the air doesn't come out. We opened 2 of the 3 packages purchased to see if the first was fake but the second was exactly the same. We tried spraying them with water from the sink. We tried soaking them in water but nothing helped. I'm…