Is it OK to turn off my fish pond pump at night?

I recently got the following question from a visitor to my web site:-

> Jim, great website, the bio filter has truly helped my pond at home,
> turning green water to clear water in under a week, thanks. Couple of
> questions for you if you don't mind!
>
> Is it ok to turn off the pond pump during the night and how often do you
> run your pump at home?
>
> Again, thanks for the great idea, I passed it onto a mate of mine, who
> built his own, he in turn passed the idea onto a friend of his and all
> have been converted away from chemicals. Won't be too long before they
> are everywhere!!!!

This year I have been particularly pleased with my bio-filter setup (detailed in my main web site) as the water in my own fish pond has remained gin clear since spring, even during the summer months.

I think this is probably a question a few people often wonder about, so thought I would post it on my blog. I now have a Titan 8000 which I let run continuously 24/7/365. If I shut it down then my stream would dry up.

Also at night time the photosynthesis process of the plants and algae in your pond reverses (just as for normal land plants). During the daytime plants absorb carbon dioxide and produce oxygen, but at night they absorb oxygen and exude carbon dioxide. So at night your plants and algae are using the oxygen - as well as your fish!

For people who have a major algae bloom in their ponds at night time this can reduce the amount of available oxygen to dangerously low levels, suffocating the fish, and they end up gasping for air at the surface of the pond.

So if anything, its more important to keep a pump running at night. This could be the pump feeding your waterfall, fountain, or even a dedicated in-pond venturi. If you have clean, healthy, clear water, and not too many fish in the pond then its not so much of a problem.

The key is to know and watch your fish at night. My wife and I go into the garden each night (she needs her bedtime fag), and to look at the fish (I have several lights in the pond), and maybe give them a bedtime snack! Night time we find is often the best time to watch them because you can see right to the bottom of the pond, and any baby fish which are normally hidden during daytime.

I have never had any problems with fish suffocating by keeping my main pump running all the time. It keeps the constant filtering and oxygenation of the water going.

I have an in-pond venturi too, which is timer controlled to run from 10am til 3pm. As well as providing air, the fish love to swim against the current it produces, and the motion of the water helps move sediment around in the pond and so get sucked up by the main pump to the
filter.

There you go!

Jim