Bacteria in substrate....?

[dally]

hey all.

Was thinking of using river sand (with a clay base) as a substrate in my new tank, and was warned about an anairobic (no idea how to spell it) bacterial build up in the sand....

So ill ask here first . How can i avoid this??

Thanks in advance :bounce: :bounce: :bounce:

[alanmin4304]

I use it all the time without any problem at all, but I am talking about greywacke sand with a little silt not clay with a little sand

[Interfecus]

Anaerobic zones will almost inevitably form in a sand substrate as water circulation is extremely poor. This can be reduced by a number of means:

1. Forced circulation of water throught the sediment. This could be done by pumping water into a looser layer underneath the sand. You could, for example, run some of the tubing used for air pumps through a gravel layer, punch small holes in the tubing to evenly distribute the flow, then place the sand on top. Fine mesh on top of the gravel could help to prevent the sand from falling down into the gravel. You then pump oxygenated water into the tubing and it will filter up through the sand bed using a pump optimised for medium to high pressure. The sand layer would have to be quite thin for this to be effective.

2. Use burrowing animals to keep the sediment mixed up. Many snails may do this.

3. Plant lots of plants with good root systems in the sediment. These will oxygenate it a bit.

With a thin layer either 1 or both 2 and 3 together would probably be sufficient. With a thick layer all three together might manage it, but if it's too thick dead zones are inevitable.

[klaymann]

sum dead zones are good for anerobic conditions ( denitrification) !! ... 8)