Ultra Phos

[George]

If you haven't read them, I highly recommend you to read several articles by Daniel Knop in recent issues(starting from Sep-Oct 2012 issue) of coral magazine, especially Nov-Dec 2012 issue. In that issue, Knop talks about differences between those 2 forms of phosphate binders. Some abstract....
(IRON OXIDE–BASED AND IRON HYDROXIDE–BASED PHOSPHATE BINDERS)...Because of its lack of solidity and its tendency to erosion, this type of phosphate binder is not optimal for a fluidized bed filter. It is better to put it in a fixed bed filter, where the grains will remain immobile even as the water is continually sucked or pushed through. However, the material must be very well rinsed beforehand—otherwise, any existing loose particles may form the fine sediment described above.

(ALUMINUM OXIDE–BASED PHOSPHATE BINDERS)
In principle, this material is very suitable for a fluidized bed filter, as it produces no eroded particles even under these conditions. But you shouldn’t use too much at once; around 1 pint (500 ml) per 1,000 L of tank volume will suffice, and to be safe you should always start with a smaller dose.