Claire,
Are you saying you have the proverbial "green water" ?
i.e. you have an algae bloom so the water looks like pea soup ?
If yes then presume you do not have an Ultra Violet (UV) light fitted in your system ?
With a correctly rated wattage of UV for your pond size,
( 10 Watts per 1000 gallons as a rule of thumb ) then it should help to clump
the algae together so that your mechanical filter can strain it out.
If you do have a UV fitted already then what is the flow rate through your filter
as if it's too fast then the UV light may not have contact time with the water to work ?
As for flushing your filter, whether you do it once a week or perhaps every day
should make little difference as long as you fill up with dechlorinated water
and the overall water change is not large. 10% of the pond water volume per week
is a good starting point.
Hope this helps a little ........
Posted on May 7, 2009, 10:10 AM from IP address 81.137.222.103