I did read that Alfagrog provides 6500 square meters of surface area per cubic meter of media. They claim it will handle 2kg of fish food per day with just 100L (+- 50Kg).
Is this possible at all??? Sounds wrong to me !!!

Regards
Marius

Hi Marius,

Those claims seem a little high to me.

There are many claims about the surface area of filter media. However the success of each and evey one is entirely dependant on the size of the bacterial colonies that grow on them.

More mature filter medias will have larger bacterial colonies. Another factor to take into account is the way the media is placed in the chamber. The water has to pass evenly through the media to make it efficient.

Alfa grog works well. If I recall correctly it is a by product of kilns. The clay used to line kilns turns to ceramic after firing. This is then discarded.

There used to be piles lying in the veld in the Free State. I wonder if it’s still there?

Chris

Chris Neaves wrote:

There used to be piles lying in the veld in the Free State.
Chris

Hi Chris, I think it could have been lava rock lying in the veld? They sometimes look very much the same. Last year I collected bags of Lava rock lying in the veld at the Sun City Nature reserve and brought it back to Cape Town for my ponds.

AlfaGrog are manufactured in the U.K. by sintering selected fireclays at very high temperatures, resulting in a foamed ceramic porous mass. By crushing and screening the material a range of grain sizes are produced.

In the US, Alfagrog is sold as Supra.

I sold Alfagrog a few years ago and found that it is fantastic.

On one of my ponds, I only have a waterfall cascading down into a 30 liter bucket filled with Alfagrog and oyster shells before the water finally enters the pond. No other filtration apart from a sand filter, and with 35 fish in a 10 000 liter pond. I never had any Ammonia or Nitrite problems.



I am still using it in various ponds, and in my aquarium filter with great success.

If you have limited space, that is the way to go. At least 50x more surface area than bioballs. Approximately R 50 per liter.

As Chris said, it is very important to use it in a correct way. The best is to place it in veggie bags to enable you to lift it a bit from the bottom and to enable you to clean it easily. I also add oyster shells to the bags to buffer the Ph. The water flow through it is very important.

Hi,

Definetly fireclays. Straight out of a kiln. Took a couple of bags home then boiled a sample for a few hours. Let the water cool down and tasted it to make sure there were no chemicals that could be released into the pond water.

I compared it the actual bag or two of alfa grog I have and it was exactly the same.

So I have a single chamber filter with a media of mostly 19mm silica stone, 4 - 6mm gravel, some alfa grog and some lava stone. It's all mixed up now and works well.

The lava stone looks exactly like siporax - or loolitubes under a microscope by the way.

They use lava stone for tumbling jeans in the clothing industry and for hydroponics. Also a massive surface area.

Fascinating this hobby of koi keeping.

Chris