why not setup a solar panel which you can redirect the water flow back to your pond thru???, then if you find your water temp is abit high you can always bypass the panels via the redirector piece like in a pool setup. Just do a mini DIY solar setup with 15 or 20mm HDPE piping also with a redirect valve. The piping is about R1.80 a meter and wont cost you anything on electricity and you can build a solar panel on ground level so you would still be able to use a submersible pump on it.

I'm attempting DIY solar heating on my spa pool this summer, thats my next project now after my pond

Hi Cliff

Thanks for the advice and I know solar heating is a winner. When I stayed in Pta I had it on the swimming pool and it raised the temperature a lot and water was hot even late in the evening.

The only problem I foresee in a Koi pond (winter) is that you will have a high temperature during the day, but the temperature drop during the night might be huge. Hopefully by the time I need to QT fish in the new pond we will be in summer and the temp will remain in the range as required for the quarantine.

Cliff, do you just use that piping in a weave and it will work?

Not so much in a weave, easiest method is to coil it, I'll try and do a "Marius MS Paint" image

my drawing looks absolutely crap, so let me rather explain.

I would take the 20mm HDPE piping and coil it into a circle, with the outer circle containing the outlet from the pond, this would then coil around till you reach the inner bit of the coil which would then feed back to the bypass valve and then back to the pond. Obviously you cannot have any kinks as you will then have leaks. But I was thinking for a pond to mount this onto a floor standing board which is sun facing.

On your inlet and outlet you would have your joins which feed from and to the pond where you could then bypass at your discretion.

Found a pic which I saw a while ago which is an excellent example

I wonder how well this works.

Usually the pool guys say 50% of of your surface area needs to be in piping for the solar heating to be effective..

Well, you dont really want the same level of heating a pool can get, so i'm pretty sure 15 - 25% of the surface area would give your pond a decent temperature

Photos are looking good and it is a simple and cheap modification to do on any setup. As you say, you can bypass the solar heater when you don’t need it. The temperature will rise a bit during sun shine weather, but in the Free State we have cold nights during winter, so I wonder what the experts will stay about this massive temperature swing?

Will this not have a negative effect on the Koi? I don’t mind the cold temperature in the winter since I believe they need a ‘rest’ period as well. My concern is more towards QT in colder weather and how stable must the temperature be for QT to be effective?

Well, on a pool system they have pressure valves which keeps the water in the pipes...as long as there is water in the pipes the pipes will not perish, it's the moment you have heat on the pipes and then flow water thru it that it could possibly break.

The water in the pipes actually prevent it from overheating, the moment it has no water and the sudden burst of cold water flows thru then you stand the risk of cracking the pipe, thats why with a pressure valve on the system you can keep the water inside and prevent the risk on breaking the pipe.

Can that much harmful bacteria really accumulate in one evening of being switched off.

Even if the nights are cold, what harm could you really do if you run it 24/7 where you have warmer water during the day and it's a bit colder at night???

The solar heating idea looks good, we had a similar setup on our pool in our old house but actually had it running on the carport roof to heat it from the bottom and top. The temp use to get up to 31 in summer and actually had to be turned off via bypass valve.The panel was around was about 50% of the pool surface size.

I agree with Marius thought that the temperature swings may have a negative effect on the fish and cause unnecessary stress, to bring the water temperature up is fine as it will be gradual but how sudden will the drop be at night, especially if the pond is above ground as you have mentioned ??

Cheers
Lee

Let the fun begin. The pond will be 4 x 2m and less than a meter deep. Will be using 2 bottom drains and a skimmer in a 3 chamber filter system that will for part of the main structure. I will use 2 x 4500L pumps that will be mounted at the clean-end of the filter system. Each chamber will be fitted with a drain pipe and valve to clean it. I will also fit a valve on each of the 2 main drains coming from the pond for easier maintenance.
Will use 45* bends wherever possible.( Dankie oom Piet)
The pond will not be fancy at all and will mostly be used as a QT /hospital tank and to grow up fish (if I have fish left)

Hi Marius

I take its now going to be completely independent of the main pond now ?

Also are you still looking at being able to heat with the reduced size now or have decided against that ?

That digging work it real pitta, just sand everywhere.

Cheers
Lee

Yes it will be 2 ponds with no plants or fancy things in the water. Maybe a net covering it and a simple return at the far end. Will use some of my Matala sheets from main pond and fit the new 1s in old pond

Will not heat the pond now, but it might become a project later on. The return pipe will be fitted on the outside near the log cabin. Hopefully the plants will grow fast to hide the pipe. Maybe a UV as well, since pond will be in full sunlight