Thread: DTF's New Pond

Originally Posted by samp09

Thanks Dave I did have a look after and saw the 45 joints, I thought maybe I could make 2 big triangles to support which should work pretty well I would have thought. I still ideally need the sheets laying across rather than lengthways I think though, would be easier for removal and storage.

my sheets are about as big as i can easily handle,
35mm thick 2500mm x 1050mm takes about 60-90 seconds to take them off or put them back on.

had the covers off yesterday and today again...
i'm making the most of it until tomorrow when the clocks go back...

i had all the fish out and did a measure up yesterday,
thought it would only take an hour or so...5 hours later...

it was a lot more work than i had anticipated, though it would have been a lot quicker with someone else to help,
or taking the pics and doing the video.

Originally Posted by KiOgon

They're all fine fish Dave and put on some decent growth! shame about the last Sanke, just the way it goes sometimes. I have a Budo Goromo turned Shiro Muji, lost every bit of colour after a year or so, now 21 year old, never grew a lot but this year has put on a bit and started to get some purple looking shimmis coming through.

it's very rewarding to see a fish bought very small, grow well and turn into great looking fish.
thats probably one reason i have zero interest in showing fish, or even looking at them.

for every UK GC i'd like to see development pics in the owners UK pond... from tosai/nisai all the way up to the 80cm+ fish are to win GC
and not be imported from Japan as azukari at 80cm put on 2cm in the UK and win GC....

thought i'd add some winter temps to my build thread, rather than spam the main pond temp thread...
House at 19.4C a drop from 19.8C yesterday.
probably because the ambient outside air temp is down to a chilly 4.9C today from 8C yesterday..

the temperature on the TC-10 digital stat is still 12.7C, which reads from the inlet side of the drum.
but the wireless thermometer that is sat in the skimmer outside is reading 12.6C so might have dropped 0.05C last night.

the pond is insulated like a new build house though, the sides all the way down to the bottom and top has an insulation factor of 0.2 W/m²k
same for the pipework to and from and to the pond in an insulated duct from the fully insulated log cabin/filterhouse.

the bottom is completely uninsulated though, so the ground acts as a heatsink in summer and winter.
and i heat the pond, and by extension ground below the pond to 25C all summer june to end of september.
ground temperatures at 0.5mtrs if heated to 16C in summer can still be around 8C - 12C
so by heating to 25C all summer i think it must still give up heat to a higher amount,
So the bottom of the pond is basically a ground source heat lowsurface temperature radiator.
just depends on if your pond is insulated enough to hold that small amount of heat in, or just loses it....

heat is still being lost from the pond, insulation only slows the transfer of that heat.
but it is being lost slowly enough for the ground to hold the pond temperature up.
4 months at 25C will store a very large amount of heat into the ground.

the below ground temperatures are well documented by ground heatsource companies.
there are even UK maps showing average soil temperatures at different times of year in different areas.
as scotland is much cooler than down south. but these are based on the UK average day/night temperatures over a whole year.
which at a meter deep only get up to 16C max, but having a pond at 25C heats the deep ground directly.

by heating the ground to 25C in summer stores up heat for winter.
but as you say insulation is everything, slapping a bit of bubble wrap around the pipes and filters is not going to cut it.
it needs to be done all the way to the bottom of the pond and have a high insulative level of around 0.2 W/m²k
the same for my ducting system and log cabin/filterhouse.
the only pipework that isn't fully insulated is the bottom drain which is at the same below ground level temperature anyway....

but there is only a small trickle of heat from the ground, if i took my covers off when the air temperature was lower than my pond temp it would drop,
as the heat being lost would be many times that compared to the trickle of heat coming in from the ground.
and the ground would give up that stored heat more quickly due to the increased temperature difference.

the ground temperature will drop slowly over the course of the winter asit gives up heat, last year was very mild and the pond didn't drop below 12C
but we have already had a harder winter so far, so it may drop lower than 12C depending on how harsh the rest of the winter is...

you can see from this report for groundsource heatpump installers calcuations
area by area of natural temperatures, that i posted a couple of years back and used to help my new build insulation plans.
of a highly insulated pond with bare bottom

https://nora.nerc.ac.uk/id/eprint/51...ept%202015.pdf

Todays temps are up again,
from 12.7C to 12.8C due to the warmer ambient 11.5C temperature, less heat differential and loss from pond.
still unheated...

Temps still climbing, up 0.2C to 13C with the wet and warm weather...

bit of a general update, showing the Recycle R.O and big blues i've made adjustments to.
the Acers i put in bonsai training pots, and a few new bits in the filterhouse...
plus the fishy's still looking happy at 12C