19 replies to this topic

[Shane_H]

Has anyone had any experience with heating say 1000L outdoor ponds during winter?

[Ivan Sng]

Well I have tried heating a 1000L outdoor tank with a 300W heater towards the end of spring (Nov-Dec)... With the longer days and the heater, I was able to keep the water above 20degC quite constantly. In winter though, I think you would need at least 600W.

Although there could be other contributing factors that may help or hinder... buried tank? waterfall? any timer on/off for filtration or water movement?

[Dannoz]

I dont mean to sound like a bogan but back in the day our family used to heat a rather large out door pool by using a pump a drum and a fire.
Just attach the pump in the normal fashion on the side it pumps water back into the pool (or pond) attach a sufficiently large sealed drum and have some pipe on the other side of the drum back to the pool (essentially meaning you have a pipe with a drum in it ).
All you need to do to raise the temperature of the water massively is light a fire next to the drum or attach a small electric element to it. Obviousely the water runs through and gets heated at a reasonable cost money wise and this is very cheap to set up considering you only need a small slow pump.
You could get a fire going stoke it a bit and walk off and set ur pump to turn off in 4-5 hours when the fire would be burnt out. Or set the pump and ellement on a timer.
Might not sound practical but its cheap and it will work and its cheap. Wood is free. An electric element is more expensive obviousely. And it will easily raise your over night temps buy a large degree. This worked for a 9500 litre above ground pool in a place where temps could get below zero some nights.
I am going to use this method to heat a 3900 litre pool in my garage using this method. Breeders in it while they are out of season ect and maybe growing out fry in it from time to time depending on circumstances.

Hope this gives you some ideas

[mattt]

i am also interested...

i will be using a coil heater + thermostat to regulate. is it the most effective way to go? i dont know...

i have thought about those black solar mats for pools that absorb the suns rays and heat up as water circulates but how well they work in winter i dont know.

[Shane_H]

A fire heated pond? haha...not sure that would fly with the Mrs, but a good idea none the less!!!

I guess all I want to be able to do is keep the water temp above 20 deg to hold a barra or two. It should heat up to high 20/low 30s in summer. I've read they'll survive at around 20 degs, but will shut down any lower.

I've also thought of using one of those pool covers that float on the water to act as a blanket during the cooler months and keep heat in.

[mattt]

Ive seen water heating by hippies using compost bins with a large coil inside

[Krystal]

In the coming months i will be trialling a few ways to heat my 1200l pond.

The main way I hope to take the chill off is by running a series of lengths of black poly pipe across my very hot black roof tiles. Ill have a separate pump servicing this with a moderately low flow rate. There will be a heater permanently in the pond, this will be run with a thermostat. Theoretically the heater will only come on during the cooler months.

The pond will be mostly covered so this is retain a fair amount of heat and cut down on evaporation. Summer may be an issue with the cover though so its all trial and error at this stage

[Kieran]

I did the same thing at the beach shack for a warm shower. Black irrigation piping just spread out over the tin roof. You could do a nicer one on the patio roof etc etc.

I know a few people that heat their pools by pumping water up onto lengths of copper pipe on the roof (north facing).

[mattt]

any risk of it getting too hot to need a cutout u think?

[Kieran]

Definitely. Those pools get up to like 27deg C easily.

[Krystal]

My plan is to have the pump servicing the poly pipe connected to a thermostat and control box.....when the water reaches a certain temp then the pump is turned off.

If it were running uncontrolled continuously in such a small volume of water then its just asking for trouble.

I will be starting mine in the next few weeks so ill keeps ya's posted.

[mattt]

nice i am looking to do the same thing soon aswell.

[Ivan Sng]

Just thinking out loud, will convection in the pipes still create an exchange of water even if the pump is switched off?

I suppose if the pipes drain out to let air in, then it should not be a problem??? Hmm, worth thinking about....

[werdna]

It wouldnt exchange that much water would it?

[Kieran]

Probably not enough to be worried about. If it's a small diameter pipe the friction would overcome that pressure fairly quickly.

In addition to such active heating, you could use passive heating. Ie. Make sure it gets sun in the morning. Plant deciduous trees around it so it gets shade in summer but sun in winter. Try placing a large garden greenhouse over the pond.

If you get to build it from scratch, put a concrete slab or paving bits (anything with good thermal mass) under the pond to act as a thermal battery. Place the pond on the northern side of the house, or better yet in a solarium / solar conservatory in the house (or shed) itself.

The advantage of passive design is that all it costs is a little more design work. Sunlight is free.

[Shane_H]

Sounds like a brillient idea Krystal. Please keep us updated as to how your system goes. I'd be very keen to give it a crack.

I also like the coils inside the compost bin idea....could just work.

[Terry]

I have been heating a 20000 ltr pond for about 8 years the temp never drops below 20c or goes over 30c. The pond is 5m x 4m x 1m it is enclosed in a hothouse 8m x 6m x 3m which is clad with laserlight sheets, some of the sheets are removed in summer for cooling.
Heating is achieved by pumping the water through 25mm poly pipe laid out in a grid pattern on the tin roof of my fish room, the pump starts when the temp on the roof reaches 25c and switches off when the temp drops below 25c. From about mid Oct the heating is switched off until mid March.
This year I started pumping hot air from the hothouse useing the same thermostat into the fishroom, this reduced gas heating by 25%

The pics were taken 5 years ago
Cheers Terry

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[werdna]

Thats a boring fish you got in there Terry, it doesnt seem to do anything.

[Leaf Fish]

Yes it does, theres bubbles breaking the surface behind it.

[Shane_H]

Hi Terry,

Awesome idea. Do you have any pics of the heating grid? Does it take long to heat up to 25C in winter? I'm guessing you have some sort of thermostat wired into the grid?

What sort of fish are you keeping in there?