Since pulling out two large iris plants the pond has taken on a very
cloudy consistency. They must have been planted in soil, which is very
rich in clay in our part of the UK.
I was advised in here to use Alum as a flocculant/coagulant, so I've
bought a tub of what I imagine contains Alum form the pond shop. I'll
see whether it works this weekend.

As an alternative, I was thinking about precipitating the positive clay
particles using an electrical charge. In theory they should lose
solubility once the charge has been removed, but applying that charge is
the tricky bit. Has any one seen a filtration system that charges the
water in a controlled and fish safe manner. I'm picturing a large tank
with slow moving water and a couple of electrodes at 12volts potential
difference. Nothing dangerous, and well away from the fish.


--
DavidM
www.djmorgan.org.uk