Dear Abdelrazzaq Al-Tawaha, Instead of using a commercial product you might want to consider the use of mature coarse compost as a biofilter for aguaponic systems. Compost can be a source of buffering for metals provide essential nutrients. The filter material itself can be a source of denitrifying organisms which will be useful potentially in preventing the staling of the water. Biochar could be another option which would allow stable filtration if you use biochar you make want to make sure the pH is not overly alkaline. Low temperature biochar has a neutral pH which would not be problematic in the water reaction. 

Dear PAUL,

Thanks a lot for important information.

My project focus to find solution for providing aquaponics  system  important elements like potassium and other element in addition to Nitrogen. And I see some information about  agriculture by product to be biofilter.

Dear Sir.,

Thanks for your time.  

Do we really need filters. Please see following link.

https://www.friendlyaquaponics.com/2015/08/04/1714/

Thanks Dear Suresh for your response.

Best solution has given by Dr. S.K. Malhotra

 Dear Ram,

Can you send me the information  for Dr. S.K. Malhotra\??