I have a 3m x 2m pond in my back garden which homes 12 goldfish and 1 small Koi.

I have realised that I need to install a UV filter as the water quality is terrible. I'm wanting to completely empty my pond and refill with fresh water.

My question is, will my fish be ok if they are put back into fresh tap water or will I need to do something to the water first.

Ta

I've never had my own pond but have kept fish in tanks and have spent many hours on various pond banksides ;)

I wouldn't change all the water in one go. There is a thriving micro culture in the water that takes a few weeks to build up properly.
Go and get a couple of hose pipes. Connect one to your tap and trickle fresh water in to the pond. Siphon (sp) water out of the pond with the other hose pipe. Do it slowly to try avoiding shocking the fish in any way.

Uv filter best but it takes a good few days before you see a difference.
There are products for dechlorination but your best bet is go with Vidsters advice for now

If the fish seem okay tho and this is for purely cosmetic reasons leave em alone til you install a filter

My only problem is the 1" thick sludge in the bottom. I need to try and get rid of this somehow. Thats why I was going to completely empty it so I could give it a good scrub.

Is the sludge hurting anything JamesRich? I would only remove it if it was causing a problem. An inch of sludge/silt doesn't sound that bad to me.

Maybe a small Tench grubbing about in the silt would stop it stagnating?

Keep a baggie net handy for removing leaves, uneaten fish food,slugs,etc.

If you get a fine mesh one you can scoop silt out with it but I don't recommend being too drastic in one go
As Vidster says it can take weeks to restore the ecology

If you have a big water barrel or anything like, fill it with tap water. The chlorine evaporates after 48 hours, great for a top up

Just a bit of low maintenance for a few minutes every day should keep on top of it, and it's wonderfully calming when you're stressed :) Keeping the water plants in one or two areas only helps as well as giving the fish some sun cover

Originally posted by JamesRich
I have a 3m x 2m pond in my back garden which homes 12 goldfish and 1 small Koi.

I have realised that I need to install a UV filter as the water quality is terrible. I'm wanting to completely empty my pond and refill with fresh water.

My question is, will my fish be ok if they are put back into fresh tap water or will I need to do something to the water first.

Ta i have a uv filter fos sale if you are interested it s to be used for 1000 gallon or more.pm me if your interested

Originally posted by roughy101
i have a uv filter fos sale if you are interested it s to be used for 1000 gallon or more.pm me if your interested

Pm sent..............................

sounds too much like hard work to me id get a cat instead

That sounds about the same size as our pond, try sticking a low voltage fountain in, they're only cheap, the movement and airation cleared our pond up a treat, that and some straw stuff I got from a garden centre somewhere.

Also, loads of snails and oxygenating plants help keep the slime under controll.

I have a large pond with around 25 Koi.
The UV light does work to kill bacteria but it all comes down to the filtration that you have and the UV bulb only has a 6 month life.

I vacuum my pond once every 2 months with a pond vac, to pick up any sludge and clean my pump filter once every 3 weeks.

To change the water, I would only empty the pond by 50% and then trickle the tap water down the waterfall so that the chlorine can dissipate.

I have tried useing the chemicals available but found them to be expensive and more trouble than creating a natural biosphere useing plants and snails.


The water hyacynth is possibly one of the best plants to put in a pond for cleaning the water of impurities and ammonia.

As to your fish! if you do empty the pond and fill it with tap water.
Wait at least 24 hours before re introducing the fish.
There is a chemical that gets rid of the chlorine but this would work out expensive due to the size of your pond.

I take it your pond is 6m3 or 6000 litres.

Sounds like the same size pond as i have, you cant just clean the pond its not that simple, first you need something large enough to put the fish in, empty the water and clean the pond to your content, when you have re-filled the pond with tap water you must leave it for 24 hours first !!! you cant just put the fish back in, WHY is you pond :gag: do you have enough plants/crispa etc?? i dont use a filter, i only have a small fountain, which is enough to help put a little oxygen in the water, you can buy some little bug friends for the pond and fish from your local water garden shop (redworms etc) there is also some, Algae Killers..((Interpet Green Away)) is a floculant It clears the pond water safely by clumping the algae together so that it sinks and is either broken down naturally. The key to a good pond is to get the balance just right to support your fish, keeping a fully clean pond isnt always a good idea for your fish.. lots of plants...crispa..clear water..oxygen etc:
good luck.

:thumbsup: