8th August 2008 at 1:11 pm #741
Hi
Have a look here: http://biosandfilter.org/biosandfilter/index.php/item/289 – hope that answers some questions. I’d say 50cm is preferable but the concrete sand filters often have about 45cm only.
Eric
Hi
Have a look here: http://biosandfilter.org/biosandfilter/index.php/item/289 – hope that answers some questions. I’d say 50cm is preferable but the concrete sand filters often have about 45cm only.
Eric