I have a odd filter question. Does the filter for my system need to be able to handle my 125 gal tank or just my 30 gal sump?

I thinking you need a filter that can handle 150GL total. if yo9u have that mych water. But than again I am not sure what filter you are talking about, so I can notbe sure

that is what I thought. I was getting some strange advice from a guy at a fish store. I need to buy a better cannister filter so I wanted to be sure I bought a good one that would handle everything

Are you running a skimmer on your system? The same rule would apply to the skimmer. You want your filtration equipment to be able to handle more than you total water volume.

my skimmer is big enough but I need a better filter. Any recommendations on a canister filter?

If your running a skimmer I bet the canister filter you currently have is fine. There are many people that don't even run canister filters due to the headache then can caused when not clean regularly. I'm not familiar enough with canisters to make a recommendation but someone should chime in a few to help you out with that.

any opinions about Eheim or Rena canister filters?

Do you have a reef of FO tank? I'm just curious why you are running a canister filter.

I've read/heard nothing but good reviews on Ehiem canister filters. I have no experience with Rena.

I personally don't like to use a canister filter just for the maintenance factor. I use a phosban reactor to run carbon and that's coming off soon too because I don't even like cleaning that out.

Right now I have a few fish but I plan to grow to a reef. I am asking about a canister filter (or any other kind of filter for that matter) because I have such large debris. My skimmer seemed to do good job, but lately with a Red Slime over run and couple rounds of Chemi Clean the water is murky and I can see larger pieces of "stuff".

From some of the above responses it appears my skimmer should do the trick.

Am I just being impatient?

You probably need to do another water change and replace the carbon in your current canister filter (if you haven't done so already). What skimmer do you have? IMO, a skimmer, if sized right should be enough while occasionally running carbon to polish the water.