After researching on the net, realised that there is no need for a dosing pump to do dosing of foods... Any equipment that can provide constant mixing of the food content in the water and have a airtube size outlet that can be controlled with a air valve is sufficient.
Such as Kalk Reactor as shown on RC's NPS subforum... Or for my case, I am using my Aquamedic Denitrator that have been sitting around for months... It provides circulation in the Denitrator and it has a airtube size outlet, but downside is I need a small pump to pump the water into the denitrator, will see if can make use of gravity feed...
Just to list out the thing that I will require if anyone is interested in trying out...
1. Airtube
2. Syringe (the tip should be able fit into a airtube)
3. 3-way connector
4. 2 pcs of air control valve
5. Foods
6. Denitrator/Kalk Reactor
I will be doing a quick one tonight and see if it will work, based on the theory, it should work...