Originally Posted by twoodrough
... Still not sure which one or ones I should use, but the info is good to have.
For a fish-only tank, I wouldn't use any of them - I'd just deal with nitrates by doing water changes. If for some reason you find you need to reduce phosphates, say for example to combat some nasty algae outbreak, then you can always add that later.
Many folks run carbon or Purigen in a reef tank to remove any compounds that are released by corals for "chemical warefare". Phosphate removers are run because excessive phosphates will stunt coral growth. There is other media out there to reduce nitrates down to near zero levels. But most of that stuff is focused on coral health, and not really the fish. So for a fish-only tank (which I'm assuming you have since this is posted in the FO
section), it's not really needed.
As far as the aluminum-based phosphate removers, they're the ones that are white. GFO
(granulated ferric oxide) based ones are rust colored.