How do you build a biological filter?

Question
    Thank you for the info. on my pond. You suggested I build a biological filter. Can you give me instrucyions on how to do this? Any help will be appreicated. Thank you!

Answer
Well, I will try, get a plastic container, of suitable size something about the size of a recycle box. Put the pump in bottom cover the pump with lava rock put in a nylon bag of pond peat cover with lava rock put a layer of air filter material big enough to cover  the area container put top off the container with lava rock. This will give you an excellent filter and keep the water conditioned. Ther are many variation of a biological filter, you may want to surf the net. If my instruction are not too clear feel free to Email me at leigh@lara.on.ca and will try to include a diagram

               I hope this helps Leigh