I've read that CC is a nitrate trap.
I've always had cc, always had low nitrates. The key is cleaning the cc with each and every water change. I also lr and a low bio-load, and hob filter, I was running two on my 55gl when I had fish, and I had lot of inverts, and the cc wasn't that deep (the deeper it is, the harder to clean). NO way do you want a ugf (had one, removed it...ugh! yuck and crash!)
It traps nasty stuff, which you can't clean under/behind rocks. In most tanks (esp reefs) there's a lot of lr, giving you less room to clean, so it just traps the stuff. I had to move my rocks around now and then clean under them. You don't want to see what comes out of the cc once it's been sitting under something for a bit. And move your lr can stir up crap if you don't have enough inverts to keep it clean.
Plus, ime, it's a pain in the butt to clean the cc every water change, you can't get any fish or inverts that will mess with the cc (they'll release the trapped crap into the water and cause nitrates to increase).
I removed all my cc, I'm going to add sand once I get the money (have the sand, just not the bins to hold all the water)
So, I can't yet say that sand is better, it's just what I've read, over and over, and over again.
My 125g has CC on the bottom, but I take it that sand is better. We thought about doing the sand but my pet store said it would make a mess. Could someone plz tell me why sand is better? Wish I did sand now
