There are two ways to use Rowaphos.
The preferred method(active) is fluidized.
The second method (passive) is to place it in a filter bag in a high areas of the sump. I personally have never used it like this.
For the first method, many people use a TLF or similar fluid bed filter. It allows a controlled rate of flow to pass through all the media.
Dosage rates vary considerably on every tank. An important thing to consider when using some types of FBF, is that they need a minimum amount of the media for it to fluidize properly. I always use the minimum amount the reactor will allow and adjust the flow rate so the media is slightly tumbling.
At a measure, I would say I use 4-5 tablespoons for around my volume of 600 odd litres.
What is your phosphate levels?