I have an ego and didn't care for the stock batting that came in the carts. So I went to fluval thought I liked it but then started pretty fast having to top off all the time couldn't pull a lot of liquid through it without topping off all the time only 4-5 drops. Just went back to poly fill but put very little in like half of what was stock enough to keep it from leaking but loosely packed. I am noticing better taste and longer between top offs. I didn't overfill it with fluval either. I also noticed more moisture around the outside of the cart with the fluval.