Fluidized bed filters questions from a noob

[jmadden93]

A friend gave me 2 "Red Sea Merlin Plus 120 Fluidized Bed Filters". I'm new to this type of filter (have only really used a sump, bio balls, protein skimmer as my filtration for my FOWLR tank) and from what I gather it helps keep phosphate & nitrate levels down but I don't know how effective they are. I have a few questions.
1) What's the benefit of this filter to my system that already uses the above filtration? Is this replacement for other filters or a supplemental filter? Worth using?
2) How does this compare to a "2 little fishes phosban reactor" and of the two which would you choose? (I could sell these and buy the 2 little fishes model for about $35)
3) What type of media do i have to buy for these filters? Thanks for your help!
Product Info Link:
Red Sea Merlin Plus 60 Fluidized Bed Sand Filter
Here is the manual from the "Merlin Plus 120":

 

[snakeblitz33]

It doesn't reduce nitrate or phosphate. It just provides a medium for aerobic bacteria to convert ammonia and nitrite into nitrate. It helps with overstocked tanks such as those at fish stores who have trouble keeping ammonia down. It uses a special type of sand that you can purchase online.
Phosphate reactor is much better for controlling phosphates and other organics.

 

[saxman]

I'd go with the phos-ban reactor as well. I've never been a fan of FB filtration for this reason: if you ever have a power outage or pump failure, the FB will quickly pack down and go into oxygen deficit, which means the bacteria will die, thus releasing nasty compounds in to the water. You'll also have to replace the media and start all over with cycling it. This can however, be somewhat mitigated by using floating media rather than sand, which won't pack down upon loss of flow.