I wanted to use a supplemental sponge filter with an air stone for my tanks. Two main reasons:
1. extra filtration and gas exchange
2. seeding new tanks
I am a new fish keeper with one cycled tank up and running, and two more waiting in the wings. I of course went with Aquarium Co-op sponge filters. The blog posts & vids made set up a breeze, but I think I may have overshot the mark on size vs. purpose.
I bought a "Small" for my Fluval Flex 15, based on the product description, but it takes up a lot of space in the tank and is moving a lot of air/water with the Ziss stone in it. The OE filter set up on this tank has great flow already and a multi-position head that is very adjustable. I just bought a "Medium" to go in the Flex 32, but after setting the small up in the 15 today I am thinking I've purchased 2 oversized set ups.
My question is essentially this...when you are using these in addition to a good primary filter, should you be going down a size or maybe even two from the recommendations on the website? Is there even more to consider if they are or will be planted tanks (CO2 diffusion)?
Thank you for taking the time to read, and I apologize if this is an FAQ that I just couldn't find.