Bio or no?

[ginalynn]

I have been looking at mechanical filters and protein skimmers lately and have noticed that, for example, with the CPR Bak-Pak there are two models of protein skimmers. One has a fine plastic like ribbon that the water goes through after the skimmer and acts as a bio filter and the other model says that it is for reef tanks because it does not have the floss so therefore it does not collect nitrates. I am confused about this. Everything that I have read says that nitrates in a tank are bad, so why would they even make the one with floss if you don't want the nitrates? I want to make my current FOWL tank into a reef tank someday, so if I ordered one I am assuming from what I read that I would want the one without the biological filter built in. Is this correct? Where does the difference between wanting the one with the floss and wanting the one without lie?
Thanks!! :help:

 

[cmack]

First off, nitrates are more harmful to corals than to fish.
In a reef tank, the combination of water flow (from power heads, and filter), and cleaning crew should remove the bulk of the larger waste, so if done right, you shouldn't need a screen/floss material.
On a fish only tank, it will help to remove larger particles from your tank, but you will have to clean this material regularly so it doesn't restrict water flow, or allow Nitrates to build up too high.