On 05/07/2010 12:02, David WE Roberts wrote:

Trouble is I am getting a greenish film on the surface, a net doesn't
pick up anything.

Anyone any ideas as to the film and a possible remedy.

Time is a great healer :-)

When I built a pond (a long time ago) the books I read said that I
should expect it to be green and murky for a while until it established
a balance.

After that it should be fine as long as no nitrates are added (which
come in via tap water, compost which is not specifically for pond
plants, dead leaves etc.).

As already advised, you also need green plants to provide some shade and
to remove the nitrates from the water.
The ones you have in already will no doubt fullfil this function once
they are established.

Your comment about the nitrates is exactly what my daughter's fiance
says about his marine fish tank and indeedit may well need time to settle.

I did previously have a pond (butal liner) in a shady area, don't recall
problems with algae but leaves were a major problem.

Got a leak so filled in hole and got a prefabricated one, pleased so far
but one of the nice things about a pond is the reflection which is not
too great at the moment

Geoff Lane