fluidized sand filter

[tmik]

The reason why fluidised beds are such effective biological filters is the constant churning and aggitation of sand (media) where the nitrifying bacteria colonise results in continuous abrasion so the bacteria is constantly torn off. Luckily the sand is irregular shaped so some bacteria does remain and the bacteria is forever trying to re-colonise the media. This "young active" stage of growth is the most effective at removing nitrite and ammonia.

2007-07-05

Great information !!

How often do you recommend changing the media, or do you just top up when it is no longer up to the "Minimum" line when the filter is turned off???


Thanks,

tm

 

[duke33]

learning every day. thanks for the input ya'll.

 

[fishdance]

tmik,
Thanks for the PM - sorry for delay as I dont keep track of my comments.
Your media will wear down slowly or you might lose some during power stop-starts so you can just top it up as required. There is no need to ever change or replace media since it is inert but try to get the same type of media so the "churn" characteristics are uniform. If your below the minimum level, your filter is still working but could be working better. I wouldnt worry as they are incredibly effective as biological filters.

Filter is not really a good name for this device since it just keeps a lot of bacteria active and alive with fresh food (waste) and oxygen. It doesnt really filter any particles out unless you install a mechanical pre or post filter.

 

[duanes]

I use aragonite sand in my FB, it wears out faster, as the calcium dissolves, but my purpose is to help buffer alkalinity(in addition to the nitrifying benefit). I just ad more when the media volume is noticably less.

 

[cbfreder]

I use aragonite sand in my FB, it wears out faster, as the calcium dissolves, but my purpose is to help buffer alkalinity(in addition to the nitrifying benefit). I just ad more when the media volume is noticably less.

Definitely a great solution. Does the aragonite sand "fluidize" like finer sand or does it stay in place and filter like a pool filter?

Brandon

 

[duanes]

It fluidizes nicely, but as the calcium dissolves, the particles get smaller and lighter and get blown out of the column. The 200 micron filter micron sock hanging on the efflient pipe catches the "dust".