Simply Koi and More Koi

yes Syd i agree with that, to make it a bit clearer, i wrote that article for the for the march issue 2011, and i had been playing around with the idea for a while, after similar to above on a dark grey glass fiber garage roof, i had 30m of black plastic hose pipe, which gave a good account of itself. but i was only looking to give the topping up water during the water changes every couple of days, a boost, Later in the year when the sun was strong because i couldn't get every last drop of water out of the system, i ended up melting and distorting the unit. So it definitely worked and i was surprised at the efficiency.The speed of water running through the system had a very large bearing on the out come, so to replenish about 8" of water in the pond that held 4500gals over a period of about 4-5 hours with the input water temp. of 9-10 degrees i had no problem with an output of 21-28 degrees. the thought of running a output and input from the pond did occur to me, and i think without a doubt the transfer of heat would have benefited the pond greatly. But i was only interested of upping the mains water input temps. and not using any extra pumps etc. Sorry to have highjacked this a bit but the thought of something for free such as water heating does intrigue me.
It would be of interest how 'Kimr's ' heat box is running, what is the flow rate of that setup?

regards

Hi John

To be honest as it was only a trial, I have ended it as it was really to small to make any real differance but there was an increase of 1 degree and the tempreture held for longer going into the night. But the princible worked. Considering it was a very small mock up I was very pleased with the results, to be honest I didn't think the tempreture would rise at all as it was so small. I am still thinking about whether to stick with a box system or a smaller version of what Thorny did. I am moving in a few weeks so until I have the new house I wont know what going to work best, but I am looking forward to getting on with it, it is just annoying that I have to move again

I will keep you updated when I can