David Lock

I have a medium size pond (about 4k gallons) which is home to about a dozen reasonable size Koi.

This has a submersible pump which takes water into a standard filter system and back into the pond but the return pipe feeds into the top of a waterfall type arrangement and back into pond.

In winter I turn off the skimmer and air-stones but leave the pump etc going. In this weather the waterfall stops the pond from freezing completely.

But I think the aficionados advise turning the pump off as it make the pond slightly colder.

I am worried that if I turn it off the whole pond will freeze and I think fish need an air gap in the ice (( can't afford a heater)? Also I will lose any bacterial action in the filter even though it nearly all stops in the cold.

But if I leave it on in the extreme cold then the whole damn lot might freeze and I could end up pumping water all over the garden as it overflows.

So what do you pond peeps do?

David

sarasquares

iTrader: (1)

I have left my pump running so far. The water is frozen on top but not around the pump so its allowing some breathing space for the fish. I dont know if the pump is slightly warm and maybe this is stopping it freeze over.

I think fish slow down when its very cold and dont need so much air.

David Lock

OK - thanks, I think I agree with you. But do I drain the whole filter system or leave it full of static water?

Also I use a large wheelie bin as an additional settlement tank and I have a slight worry that if this freezes then it will crack. David

AnnieN

Mine is the same, I tend to leave mine running all winter

TelBoy

Guy i work with had a new pond installed last year, the cold has cracked the concrete base, the water level has dropped, and about 6 decent size Koi have been frozen solid

dunx

iTrader: (3)

A 60 watt pump is kicking out plenty of heat, mine runs constantly to filter a (very much) smaller pond of around 650 gallons packed with Orfe, Koi, tench, etc. The moving water stops it freezing as readily, mine (smaller fish) were even feeding just before xmas.

dunx

Spoon

David, I've had 2 large 'natural' ponds of 13000 gallons each for 18 years. This winter's prolonged freeze is posing many pond owners some difficulties. I know of a few Koi owners that use Nexus filters that have frozen for the first year out of many years of ownership causing a few headaches.

On one pond I have a large vortex and 3 Big Bertha multibays, totalling some 13ft long x 3ft wide x 3ft deep and a 16000LPH pump keeping the water moving. My filters have air stones on too which helps a bit more. I have water running through the 4" return pipe but at a reduced rate. This is largely due to the pump's 'Seasonal Flow Control' valve that automatically slows the pump down when it senses cold water. At least I still have a clear area of water in the pond when the rest has frozen over though.

Even though the filters aren't actually working in winter like they would be when the fish are eating and producing waste, you won't get many people in the know telling you to turn the pump off. However, In your case with a waterfall return it would be always be advised to leave the pump on at your own peril. Can you not lag your filter at all? Is it frozen inside now? What make and model is your filter? What size pipe is your inlet/outlet? If you turn the pump off be careful the water already in the pipework/filter/UV doesn't freeze and crack everything.

Ideally you could do with a separate return to your pond this time of year, bypassing your waterfall return. Just a simple pipe to return under water would be better.

I'm assuming you have maybe a 9000LPH pump with a turnaround requirement for a 4000 gallon pond? If so this should generate enough flow to prevent freezing but only if it was concentrated towards a return direct to pond pipe and not an 'open to air' waterfall.

Turning the pump off would indeed allow the entire pond to freeze over and then you'd need to make a gas escape hole, on a regular basis, somewhere in the ice. Never hit the ice though. It'd need to be warm water poured on carefully. That said it soon refreezes so it would be a full-time job.

You don't say how deep your pond is either? A submersible pump can always be lifted nearer the surface to allow it to work the same AND for the fish to settle in the water at the bottom, relatively undisturbed. I leave my pump on the bottom because of the size of the pond where the fish have plenty of room elsewhere to go.

Water is at 4 degrees at a reasonable depth. It is only the surface that is colder, hence it freezes and the reason fish lie on the bottom of most garden ponds.

It is a tough one to be honest, but either way you have some work this year that other years haven't come close to throwing at pond owners. I'd go for the separate return and lagging, myself, with the pump left on.

Quasi Modo

Would covering the pond make it worse? What about some sort of moving floats to keep the water from freezing? I've only ever had a little pond with a couple of Goldfish and frogs (they love bacon as tadpoles btw) so on a much smaller scale (forgive the pun)

Spoon

Covering the pond with either polycarb panels or a poly tunnel, even without heating, has to be better than nothing. Most ponds aren't built with fish in mind from the onset. If they were they'd be gravity and not pump fed, have bottom drains, built in skimmers, be insulated, heated and covered, ETC.

Floating a ball has worked in the past for some pond owners but this year I doubt that would work.

David Lock

Thanks Spoon for that very informative reply - this can't be Scoobynet can it

OK some basics. Pond is only about 4 ft deep at one end where I have put in sump shape to sweep pond floor into and collect debris. Submersible is a 15,000 litre per hour Aquamax (perhaps the next size down?) which I have about a foot off the floor at one end of the pond. I don't like it sitting on the bottom in case something goes wrong and pond is completely drained by mistake.

Filter and water feature are at the other end with return pipe (5"?) feeding through a dwarf wall with water falling onto a number of paving slabs and then into pond. A Cockney Koi (??) filter.

The fish have a favourite place on the bottom in cold weather but this is not at the deepest part but at the waterfall end. Odd.

Filter is an old fashioned type and only just big enough (all I had room for). 2" inlet into spray bar and bristle brushes then water tips over into filter compartment forced to flow upwards through matting filters and then into smallish settlement area and then exit. But I have added a big wheelie bin as an additional settlement tank. But I do have a bypass pipe about 5 inches diameter which I can, with difficulty use to bypass waterfall which I have used when trying to seal the paving slabs.

I think I can prevent the filter from freezing if the pump is working but the biggest danger is ice build up on the waterfall slabs which could mean the water just spilling over the edge into garden area.

However it lasted through last night when it really was pretty cold although I couldn't sleep worrying about it

So I might try and find that bypass pipe and put another cover over the filter unit.

David

David Lock

Sorry not a very good picture of what I am trying to describe. Pump is at this end and filter and wall are at top left far end.

d

sarasquares

iTrader: (1)

Nice pond

What about a pond heater? I assume you can get one for a pond. I have a submersible pump so the housing is in the water and the heat generated is keeping the water from freezing. I only have a tiny pond, its an old barrel so it wouldn't take much to freeze it solid so the pump must be keeping it just above. The fish are still feeding and active so far even though most of the surface is frozen.

David Lock

Thanks Sara. But I dread to think what my household heating bill is going to be so I have to draw the line at even a small heater for outside!! David

Spoon

David, your pump is powerful and should keep your filter from freezing. The 15000 is the earlier one to my 16000 Eco. The difference is the 'Seasonal Flow Control' on mine and probably more importantly today the cost to run. Yours from memory is 250watts and mine is 170watts reduced automatically by 40% in the winter.

4ft deep is fine too, as is the fact you have your pump lifted to avert a possible draining disaster. I'd be surprised if the pipe is 5" as normal land drainage pipe (brown) is 4" and the equivalent aquatic pipe (black) is 110mm. In any case 4" is huge and ample. Not only are you getting the water in quickly but away quickly too.

A separate issue though, and not to concern you now, is making sure that your 15000 lph pump isn't too quick for the size of filter to actually be working as effectively as possible. Your pond is technically turning around every 1.2 hours and the flow through your filter must be fast, possibly too fast to allow bacteria to grow.

So that leaves 2 things. 1) Prevent the filters from freezing/blocking then spilling over and 2) Make sure every drop of water taken from the pond gets returned (even after the filter).

Lag the filter and bypass the waterfall has to be favourite.

sarasquares

iTrader: (1)

You would think that a safe chemical would be available that you could add to the water to stop it freezing, sort of antifreeze for ponds

What about turning the pump off and using a small heater instead? You would save the electric by not using the pump and use it for the heater. The fish are not doing much at the moment so a pump is a waste of time i would have thought. If you did have a small heater then the fish would come to the warmer water so you wouldn't need the whole pond heated. And if you had the heater near the pump that would save the pump from freezing up. if that was a problem.

Chip

David,

That looks lovely.

Chip

Spoon

Sara, a submersible pump won't stop the surface freezing which is necessary for gasses to escape. I assume yours is simply vibrating in something as tiny as a barrel, causing movement to keep it clear. Koi also shouldn't be fed below 7-8 degrees (some say 10). The food will only remain in their bodies and rot and lead to death.

Pond heater comes in all sizes and often gas ones, although dearer to install are cheaper to run than say a 3KW electricity heater.

sarasquares

iTrader: (1)

Most of the surface of mine is frozen except around the bit of the pump that comes out of the water. I assume the bottom water is slightly warmer so that is melting the ice as it comes out of the outlet. I think mine is about 2ft deep. I have 2, 2/3" koi in there that i have had since the summer. so far so good.

So could David turn the pump off and install a heater near the filter? Would it stop the fish from being frozen?.

dunx

iTrader: (3)

A heater would only have to maintain a "blow hole" not thaw the whole pond...

LOL

A good old fashioned light bulb would do, 100% waterproof enclosure of course...


dunx

sarasquares

iTrader: (1)

I know that you cant heat the whole pond.

As i said before the fish would come to the warmer spot and then not get frozen, wouldn't they? Do fish have enough brain to do that?

David Lock

Spoon, yep I do have an oldish pump with no flow dampener. But it will be losing quite a bit of head as water gets to the filter. e,g. 9 metres of pipe, sharp bends into UV filter and then spray bar not to mention debris clogging up the pump casing! So perhaps 60% efficient?

Sara, a heater, even a small one, would have to be quite a bit more powerful, and hence cost a fair bit more, than a 250 watt pump unit so that rules it out I'm afraid. Thank goodness Koi seem fairly resilient buggers! My one Tench gets cross because pond floor has nothing than he can hide under.....

Thanks Chip.

David

Quasi Modo

Not a 3 bar heater then? I wondered where i was going wrong.

Quasi Modo

Are there any plants that might help to keep the pond from freezing over? ya know the way that water lillies float at the top, just thought some sort of plant might keep a gap at least for its own sake and so help the fish below as well. Some might have a natural antifreeze?

Quasi Modo

Er, just a tiny bit larger than mine.

sarasquares

iTrader: (1)

Most plants die off in the winter. Those that dont are cold blooded and are as cold as the water and are dormant if you know what i mean. I think my fish ate my lilies

I mentioned the 'antifreeze' but i googled it and there seems to be nothing out there. You would think something would have been developed by now

SimonD

I've got a 100,000BTU pool boiler in the garden you can have .
I'm glad I filled that bloody thing in last year. I wince when I think that we kept it heated through the winter one year.

Lovely pond though David.

sarasquares

iTrader: (1)

A neighbour has a jacuzzi on all year round, and he uses it. He has rood parties with lots of much younger women than himself. When he takes the lid off the steam that comes off is amazing. I bet that must cost a fortune to keep running.

Quasi Modo

Your fish weren't Kamikazi koi were they?

No development eh?, er, i'm just off to do something, nothing much, carry on.

sarasquares

iTrader: (1)

They will be if they do it again when i buy some more.

I couldnt work out why the lilies were dying as they were ok at the pot level. It can only have been the fish eating through the stems.