for my new greenhouse for next winter.

http://www.teambuy.ca/products/28138078?utm_source=ExactTarget&utm_medium=Email&utm_campaign=PRODUCTS++20120603072152&utm_term=114080

It looks like a length of black corrugated hose inside a dome on a black base with an input and output. I'm sure I can DIY something similar to heat up my 110g black koi pond inside my new greenhouse, which would then passively heat my greenhouse during the winter. ie. use the sun to heat my pond to heat my greenhouse.

Any thoughts?

BTW, Vancouver/Burnaby, BC Canada never gets too cold in the winter. Usually above freezing (ie. typically 4-6C most of the winter for the highs). Last winter I used a 42w CFL light inside my small portable greenhouse and my Improved Meyers, Eureka lemon & Calamansi tree survived all winter outside. This winter, in a more permanent structure greenhouse (6mm poly with double ply polycarbonate on top), and a 110g black Tufftotes koi "pond" heated by a 50w heater, they should do even better especially since they will be planted in ground and not in containers.

Hi, I am a Fish (specifically Goldfish) nut.

Two things come to mind:

Make sure you put it on a timer so water is only flowing thru during sunlight hours, otherwise you are radiating heat out of your rig.

110 US gal is small for koi. Max of 1-2 full grown, and forget about 3 ft (1m) monsters. consider goldfish or a 300-500 gal tub with light stocking. My rule of thumb would be 1 full grown (30 cm+) koi per 100 USG absolute maximum. If you are getting big koi at a higher stocking rate, great, but I would doubt it. Freeland makes a nice 300 gal or 500 gal tub at a reasonable price - I like their design better than the ubiquitous Rubbermaid models: http://www.freelandind.com/fipolytanks.htm Not sure if you can get them up there, but....

Eric

Only concern I have with open warm water in a winter greenhouse is serious condensation on the greenhouse walls. I know evaporation can be dramatically reduced with a floating cover, but not sure how that'd be for the fish. They also sell long chain fatty acids that will stay on the water's surface and reduce evaporation. It's non-toxic, but will biodegrade and needs to be reapplied. I use that in my pool to keep it warmer due to decreased evaporation. Need every trick to extend the swimming season up here in Maine!

My aunt had a camp in Maine. We stayed up there all summer when we were kids. The camp was right on a bay & we dug & steamed clams almost every day. I remember it being 90 degrees out, but that water was still bone chilling...

Lobster still dirt cheap up there?

When the economy tanked lobstermen had trouble with their commercial contracts and lobster prices were cheaper than baloney here for a while. Still pretty cheap compared to everywhere else, but prices have recovered You've got me thinking, though, if I can make the expo I should bring a cooler filled with lobsters to barter for citrus!

As far as ocean temps, last time I jumped in (in August) I nearly dislocated all my ribs from the cold shock. I've had conversations with older folks in Downeast Maine talking about how they were able to walk out to some of the islands on ice in the winter when they were kids. I suspect this is due to sheltered bays that have lower salt concentration and cold winters the likes of which we haven't seen in a while.

Sounds like you had some nice summers Laaz!

Looks like we're back into cheap lobster again!
Seahorse...sorry for talking lobster instead of greenhouses...maybe if it was a salt water pond...

http://finance.yahoo.com/news/forget-hot-dogs-glut-means-cheap-lobster-prices-161429633.html

At those prices, send me a cooler full!

No worries. I actually am more of a reefer myself, than a gardener. Two years ago, I was up to almost 1000 gallons of aquariums, mostly saltwater reef tanks. I grow veg & fruits for my little girl Felicia and took up the challenge of growing citrus in Canada just because I'm nuts & like a challenge. One day I hope to make a trip to the East Coast for cheap lobster. Just came from a big family dinner (my wife's side) at a fancy Chinese high end restaurant and a 10 course banquet including two lobsters is $395.00 + 12% tax + 10% tip. So about $500 for tonight's dinner. Ouch. Glad someone else picked up the tab.