water pump in winter??????

I'm a bit more basic than that.:D

I just buy some watercress, pick out the bits with stems, (they usually already have small roots), and throw them in the pond.

In a couple of days they orientate themselves and start growing masses of root.
I do also have a fair bit of elodea growing which the watercress tends to gain some support from.
Throw some in a bucket, it tends to float.:WINK1:

 

Me again

I'm finding it impossible to 'balance' this small pond so DO need some sort of filtration system. I've tried something made by King British, green algae control for ponds, but to be honest there is NO significant change to the condition of the water. In fact the water smells!

After instalation, do I need to run a filter all year round?

 

Hi, most "add a splash" potions and lotions only clear one thing, your bank balance.
As I mentioned before, there is no definitive "list of ingredients" that will balance your pond, if there was, the UV and bio filter would never have been invented.

As for a filter and UV we need to go back to basics to understand how they work and what you should do.

The pump sends water through the UV, the uv causes micro organisms to clump together, these organisms are now big enough to get trapped in the foam filter layers of the UV. If they were not trapped the water would turn green. (Which it has in your case)

The bio-media in the filter is where all the real action takes place.
The bio-media gives the good bacteria some where to live and multiply, in short they convert all the fish waste into fish paste (I just made that bit up as it sounds good)
But they really do convert the fish waste into something not poisonous.

The good bacteria need water and oxygen as well as waste to live, so come winter time turn the pump off and, oh dear, no water or oxygen, the good bacteria die. (It takes a couple of hours but they do die) Switch it back on in summer what have you just done? dumped a load of dead organisms into the water.

In winter time you can however raise the pump up (Shove a brick under it) to reduce the cooling effect of cold water you are circulating, you can also turn off and remove the UV (some folk fit a by pass pipe and taps for this reason)

You need to clean the filter sponges as and when in pond water, as the chlorine in tap water will kill the good bacteria, change the UV lamp at the beginning of the season.

The UV should be big enough to cope with the flow, the flow should be the whole pond volume once ever 4 hours minimum. (Some folk say once every two hours, but that's really only for a well stocked koi pond)