On Thu, 06 May 2004 02:08:19 +0000, RichToyBox wrote:

The bead filters are just sand filters with the flow reversed, using
polyethylene beads. I think that some of the manufacturers actually are
able to buy a backwards control valve, but some just take the plumbing
apart on the inside, sending the current down pipe from the bottom to the
top, and vice versa. The bead cake will sometimes glue itself together
with the biofilm, so the better filters have installed a jacuzzi blower
and mounted it on the intake piping so that during the backwash, the
blower sends a lot of air up under the beads breaking the bead pack. Look
at some of the bead filter manufacturer's sites and they show the internal
plumbing and the mounting of the blower. See
http://www.pondtech.net/PDF%27s/CHAL...N%20MANUAL.pdf and
http://www.sacramentokoi.com/comparison.htm

Thnaks for the explananyion and the sites RTB i will have a look and
decide if I will try and modify the filter or use it as is.

Trev