Experiences with GFO, Helpful or Harmful

My system is 46gal bowfront so Ill make a rough estimate of 40gal of water. No skimmer sump or fuge to hold any extra volume. I used the BRS GFO and used the suggested dosage of 1 tablespoon per 8gal and did 5 tablespoons. It was placed in a HOB filter, washed very well. It was in a pouch with 2 layers of 100 micron filter pad in front of it to prevent any small particles from entering the system and the 1st layer did show some staining as a result but nothing major. After a week or so I took out half the dose since it seemed to be too much for the system and for the following 4 months changed it only twice with 3 taplespoons each time.

Im thinking I shocked the system at first and that is why I gave it a really long time to try and ride out. After 4 months though enough is enough and I decided to remove it. I had it packed semi tightly in the HOB filter which would prevent any erosion of the GFO and since water flow was restricted to a HOB filter with a rate of less than 200gph and not all of the water entering the filter passing through the GFO and back into the system the GFO would be very in-effiecent in my system compared to one using it in a reactor.

 

Is there another GFO calculator out there besides the one on the BRS website?

 

I know of none. I suggest using the rate that Azdesertrat suggested.

 

Two Little Fishies recommends no more than 10 grams per 10 gallons or about one level spoonfull. Personally I prefer half that 24/7/365 as a preventive measure, cheap insurance.