Yea, you need more filter. And bigger water changes possibly. I change 75% every week. I have a 2262 and a 2217 on a 125 with smaller fish than you have. It's not that I need more bio-filtration, it's just that Eheim's have kinda low and slow flow. I think that low flowrate is not enough to keep tanks with big fish clean enough. So add another canister, or add something for purely mechanical filtration. Just turn over more water and you'll have a much higher likelihood of achieving clear water.
Another thing you might try is putting a couple layers of Poret foam in the 2262. Search on here for posts by/involving a user named deeda. She has posted all about the things to put in a 2262 to make it more awesome.