Hi Chin Lee,
Bayoxide is a registered compound (essentially a Granular Ferric Oxide/aka Iron Oxide) that was developed by a company called Lanxess. They essentially have 3 flavors: Bayoxide E33, Bayoxide E33P, Bayoxide E IN-20. It is used in water treatment for Arsenic control which is highly poisonious to human consumption and also in industrial manufaturing for heavy metal removal (ex Selenium). The fortunate side benifit is it will bind to PO4 for removal which is how Rowaphos markets GFO (It could be a repackaged form of this stuff??..just my opinion, no actual proof).
The difference between E33, E33P and IN-20 is that IN-20 is to treat non drinking water (I'm thinking IN stands for Industrial use???), while E33 is for drinking water and is granulated. E33P is the same as E33 but is in pellet form and probably wouldn't work very well for fluidized application. I quoted you E In-20 and this is probably an error, the E33 is your better option IMO.
Here is a quote I found on the internet and you can read more about Bayoxide in the following link.
"Examples of tested and commercialized non-drinking water applications of the BayoxideŽ E33 media include:
Aquarium PO4 Removal
Mining & Metallurgical Effluents As Removal
Food & Beverage Process Water Purification
Groundwater As Remediation
Domestic Wastewater PO4 Polishing
Refinery Wastewater As & Se Removal "
http://www.severntrentservices.com/w.../bayoxide.html
One other thing - I looked into buying some Bayoxide a year ago but I couldn't locate a supplier..(maybe Univar can get it in)..
I hope this helps